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BRITISH MUSEUM (NATURAL HISTORY)
Fossil Mammals of Africa
No. 14
SOME
EAST AFRICAN PLEISTOCENE
SUIDAE
L. S. B. LEAKEY
LONDON
19^8
4 f ^
BRITISH MUSEUM (NATURAL HISTORY)
Fossil Mammals of Africa
No. 14
SOME
EAST AFRICAN PLEISTOCENE
SUIDAE
BY
L. S. B. LEAKEY^ m.a., d.Sc.
(^Curator oj the Corjndon Memorial Museum, Nairobi')
With 31 plates
LONDON
PRINTED BY ORDER OF THE TRUSTEES OF THE BRITISH MUSEUM
Issued June, 19S^
Price Three Pounds Ten Shillings
BRITISH MUSEUM (NATURAL HISTORY)
FOSSIL MAMMALS OF AFRICA
No. I. The Miocene Hominoidea of East Africa. W. E. Le Gros
Clark & L. S. B. Leakey. 117 pp., 9 pis. 1951. Price
5s.
No. 2. The Pleistocene Fauna of Two Blue Nile Sites. A. J. ArkeU,
D. M. A. Bate, L. H. Wells & A. D. Lacaille. 50 pp. 1951.
Price 15s.
No. 3. Associated Jaws and Limb Bones of Limnopithecus
macinnesi. W. E. Le Gros Clark & D. P. Thomas. 27 pp.,
6 pis. 1951. Price 15s.
No. 4. Miocene Anthracotheriidae from East Africa. D. G. i
Macinnes. 24 pp., 4 pis. 1951. Price 12. 6d.
No. 5. The Miocene Lemuroids of East Africa. W. E. Le Gros I
Clark & D. P. Thomas. 20 pp., 3 pis. 1952. Price 12s. 6d.
No. 6. The Miocene and Pleistocene Lagomorpha of East Africa. j
D. G. Macinnes. 30 pp., i pi. 1953. Price los. ,
No. 7. The Miocene Hyracoids of East Africa. T. Whitworth. |
38 pp., 7 pis. 1954. Price £1 5s. j
No. 8. An Annotated Bibliography of the Fossil Mammals of Africa |
(1742-1950). A. T. Hopwood & J. P. Hollyfield. 194 pp. |
1954. Price £2 5s. |
No. 9. A Miocene Lemuroid Skull from East Africa. W. E. Le Gros |
Clark. 6 pp., i pi. 1956. Price 5s. (
No. 10. Fossil Tubulidentata from East Africa. D. G. Macinnes. I
38 pp., 4 pis. 1956. Price £1. j
No. II. Erinaceidae from the Miocene of East Africa. P. M. Butler. |
75 PP-. 4 pis. 1956. Price £2. ’
No. 12. A New Miocene Rodent from East Africa. D. G. Macinnes.
36 pp., I pi. 1957. Price £1.
No. 13. Insectivora and Chiroptera from the Miocene Rocks of
Kenya Colony. P. M. Butler & A. Tindell Hopwood.
35 pp. 1957. Price 15s.
CONTENTS
PAGE
I. Introduction ......... i
II. Key to Genera of Suidae ....... 2
III. Systematic Description
Nyanzachoerus gen. nov. ....... 4
Nyanzachoerus kanamensis sp. nov. ..... 4
Potamochoerus majus (Hopwood) ..... 7
Potamochoerus koiropotamus Gray . . . . .12
Mesochoerus paiceae (Broom) . . . . . -13
Mesochoerus heseloni Leakey . . . . . • 14
Mesochoerus limnetes (Hopwood) . . . . • 15
Mesochoerus olduvaiensis Leakey . . . . .16
Mesochoertis grabhami (Hopwood) . . . . .23
M etridiochoerus andrewsi Hopwood . . . . .25
M etridiochoerns pygmaeus sp. nov. . . . . .26
Pronotochoerus jacksoni Leakey . . . . .28
Pronotochoeriis nyanzae sp. nov. . . . . .28
Notochoerus capensis Broom . . . . . .31
Notochoerus euilus (Hopwood) . . . . . -31
Notochoerus compactus sp. nov. . . . . -32
Notochoerus hopwoodi sp. nov. . . . . . -34
Notochoerus skull, c.f. hopwoodi . . . . .36
T apinochoerus meadowsi (Broom) . . . . • 41
T apinochoerus minutus sp. nov. . . . . .46
Hylochoerus antiquus sp. nov. . . . . . -47
Hylochoerus meinertzhageni O. Thomas . . . -48
Orthostonyx gen. nov. ....... 48
Orthostonyx brachyops sp. nov. . . . . .48
Afrochoerus nicoli Leakey . . . . . -53
Phacochoerus altidens altidens Shaw Cooke . ... 62
Phacochoerus altidens robustus sub.-sp. nov. . . .64
Phacochoerus africanus (Gmelin) . . . . -65
IV. General Discussion ........ 66
V. References
68
EAST AFRICAN PLEISTOCENE SUIDAE
By L. S. B. Leakey
I. INTRODUCTION
This paper deals with the fossil pigs collected in Kenya during the period 1931-1955
at Kagua; Kanam; Kanjera, Karungu; Marsabit Road; Olorgesailie; and Rawi: and
in Tanganyika Territory during the same period at the Crossroads Site 50 miles from
Arusha; in the neighbourhood of Lake Eyassi; and at Olduvai. Most of the specimens
are undescribed, but some have formed the subject of brief notes by Hopwood or
by me. Other specimens already described from Nyasaland, Southern Abyssinia, the
Sudan, certain sites in Tanganyika Territory, and from Uganda have been revised
and are discussed in some detail. All this material forms part of the collections
preserved in the British Museum (Natural History) and the Coryndon Memorial
Museum, Nairobi.
Apart from these, there are two major collections of fossil Suidae from East Africa,
both of them in Europe. They are, first, the pigs collected by Professor C. Arambourg
in the lower valley of the Omo River, Southern Abyssinia, and now in the Museum
National d’Histoire Naturelle, Paris, and, second, those collected by Professor Hans
Reck at Olduvai, and by Dr. Kohl-Larsen round Lake Eyassi; all these are in the
Naturhistorisches Museum, Berlin.
Many scientific institutions, as well as private individuals, helped to make the
expeditions, during which the above material was collected, possible, and to all of
these very special thanks are extended. In particular, thanks are due to the Royal
Society, the Percy Sladen Fund, the Leverhulme Research Fund, the Royal Geo-
graphical Society, the Wenner-ceren Foundation, St. John’s College, Cambridge, the
Governments of both Kenya Colony and Tanganyika Territory and Mr. C. W. Boise.
I am also deeply indebted to the late Mr. W. N. Edwards, formerly Keeper of
Geology in the British Museum, for giving me every facility for my work and to many
friends and colleagues both in London and Paris for very valuable discussions and
useful comments in the course of my studies.
I
2
FOSSIL MAMMALS OF AFRICA No. 14
II. KEY TO THE GENERA OF PLEISTOCENE SUIDAE
IN EAST AFRICA
A. Normal adult dental formula
includes 3 premolars.
(a) Very large lower 3rd and 4th pre-
molars. 3rd premolar longer than
1st molar. Molars brachyodont and
strongly rooted
(b) Small premolars, talonid of 3rd
lower molars short . Molars brachyo-
dont, strongly rooted
(c) Small premolars, lower 4th pre-
molar of Potamoclioems type and
upper 4th premolar of Siis type.
2nd premolar occasionally missing.
Talon and talonid of 3rd molars
long, often longer than main body
of tooth. Molars either just brachyo-
dont or, more often, slightly hypso-
dont . .
Nyanzachoerus
Potamochoerus
Mesochoerus
B. Normal adult dental formula
includes 2 premolars or less.
Canines projecting laterally
or forward at base.
I. Hypsodont 3rd molars,
but strongly developed
roots and clear line of
demarcation between
crown and roots.
(d) 3rd molars composed of relatively
few pairs of pillars. Roots very
strong. Root of talonid very
strongly developed, even in young
animals
Pronotochoerus
(e) 3rd molars composed of five or more
pairs of pillars, roots of talon of
3rd molars short and divided
Notochoerus
(f) 3rd molars composed of one or two
pairs of main pillars, \vith talon or
talonid composed of very many
small pillars
M etridiochoerus
II. Brachyodont 3rd mol-
ars, strongly developed
roots.
(g) Pillars of 3rd molars developing
into well marked cross ridges
separated by wide vaUeys
Hylochoerus
EAST AFRICAN PLEISTOCENE SUIDAE
3
III. Hypsodont 3rd molars,
(h) 3rd molars composed of parallel
no clear line of demar-
rows of pillars, the laterals paired
cation dividing crowns
and the medians unpaired. Four or
from roots. Roots, when
more pairs of pillars usual
Tapinochoerus
developed, often only on
1st and 2nd pairs of
(i) 3rd molars composed of cusps
pillars. Pulp cavity re-
arranged in three rows, but not in
mains open for long
pairs as in Tapinochoerus. Median
time.
line of pillars continuous and some-
times double. Lateral pillars with
‘Y’ shaped enamel pattern. Canine
teeth with cancellous tissue in
middle and only thin wall of den-
tine and thin enamel
A frochoerus
(j) 3rd molars composed of cusps
arranged in three or more rows.
Anterior portion often more com-
plex in arrangement. More pillars
in talon area than in anterior part
of tooth
Phacochoerus
Normal adult dental formula
includes 2 premolars or less,
but upper canines facing up-
wards at the base and face
fore-shortened.
(k) Upper premolars reduced, almost
vestigial. Face very short
Orthostonyx
4
FOSSIL MAMMALS OF AFRICA No. 14
III. SYSTEMATIC DESCRIPTION
Order ARTIODACTYLA
Family SUIDAE
Genus NTANZACHOERUS nov.
Diagnosis. — A genus of Suidae with enlarged 3rd and 4th lower premolars
resembling those of Tetraconodon Falc., but more laterally compressed. Upper and
lower molars closer to those of Sus than of Potamochoenis. Lower canines of verrucose
type.
Nyanzachoerus ka name?! sis sp. nov.
(Plate i)
Diagnosis. — A species of Nyanzachoerus of medium size and with the length of
the dental series P3 to Mg greater than 150 mm. 2nd premolar much reduced, com-
P - X 100
pared with the very large P3 and P4. The index ^ ^ above the range of Sus
and Potamochoenis.
Holotype. — A damaged mandibular ramus lacking the anterior part of the
symphysis, the incisor teeth, the inferior border of the corpus from the level of the
2nd premolars posteriorly and the ascending ramus. (M. 15882, Brit. Mus. Palaeont.
Dept.).
Paratypes. — I. A fragment of a right mandibular ramus with Mg and M3.
(Coryndon Museum). 2. An upper right 3rd molar. (M. 16383, Brit. Mus. Palaeont.
Dept.).
Horizon. — Lower Pleistocene, ViUafranchian. (Kageran pluvial deposits).
Locality.^ — All three specimens come from Kanam West, Kenya Colony.
Description of Holotype. — -The specimen (PI. i, figs, i, 2) was discovered in
1932 at approximately the same time as the Kanam human mandible. It was in
process of being eroded from the Kanam deposits and lay with the teeth still embedded
in these deposits, the lower margin of the body being exposed and consequently
damaged. The damage is of such a nature that little can be said about the essential
characters of the bony structure of this jaw. There is an inflation of the labial surface
of the jaw in the immediate post-symphysial region, which at first sight seems to be
correlated with the enlargement of the 2nd and 3rd premolars, which is one of the
characteristics of this genus, in marked contrast to the condition to be seen in Sus and
Potamochoerus. Comparison with other pigs, however, makes it clear that the inflation
is not really to be correlated with the enlarged premolars, since it is a condition which
appears in Hylochoerus and also in several fossil genera in which the premolars are
not enlarged. It may be noted, however, that the Indian genera, Conohyus and
Sivachoerus, which also have large premolars, do exhibit this type of inflation.
In Nyanzachoerus, the inflation dies away at about the level of the mental foramen,
which in this specimen is single and lies about 16 mm. in advance of the alveolus of
the 2nd premolar.
EAST AFRICAN PLEISTOCENE SUIDAE
5
The anterior portion of the symphysis is much damaged and little can be said
about this region, although it appears to have been rather narrower than normal in
living pigs. The diastema between the canine and the root of the 2nd premolar is
67.5 mm.
Incisors: Nothing is known about the incisors, which are missing.
Canines: In the specimen which is preserved, the posterior face of the lower canine
rises 32 mm. above the alveolar margin and the tooth is of the primitive verrucose
type and not of the more evolved scrofic form. At the base of that portion of the
tooth which is above the alveolus, the near face is about 2mm. wider than the outer
and this range of difference persists along the length of the tooth. The posterior
surface of the tooth is much narrower than either of the others and both the labial
and lingual surfaces are slightly convex, in contrast to the position seen in Sus and
Hylochoerus, in which the labial aspect is slightly concave. In Sus scrofa, the labial
and lingual surfaces are also marked by longitudinal ridges, but in Nyanzachoerus
kanamensis these surfaces are nearly smooth.
The lower canine in many respects resembles that of Hylochoerus more than that
of any other living genus. The enamel on the canine, as well as on the other teeth,
is much damaged by corrosion, but close examination suggests that in the living
animal enamel was present not only on the labial and lingual surfaces of the canine
tooth but also on the posterior surface below the region of wear.
FIRST premolar: There is no indication of this tooth, as there is in Sus scrofa and
Potamochoerus.
SECOND premolar: This was lost before the specimen became imbedded in its matrix,
but its position is clearly indicated by matrix-filled alveolar cavities for the roots.
The tooth was 2-rooted, but of reduced size, judged by the root cavities.
THIRD premolar: This tooth consists of a stout single cone, so placed that its apex
is situated above the posterior root. The enamel is much pitted and corroded and
does not show any of the finer detail. The gross morphology of the tooth is, however,
clear and the labial surface is more concave than lingual, while anteriorly the surfaces
meet in a keel that carries a small cuspule at about one-third of its length upwards
from its base. Posteriorly, there is a strongly beaded, well developed keel, which
meets a massive posterior cingulum. The maximum length is 29 mm., maximum
width 15 mm. and maximum height above the alveolus 24 mm.
FOURTH premolar: This is a massive tooth, which, however, is shorter than P3, having
a maximum length of only 21.5 mm. and a maximum width of 17 mm. Anteriorly,
there is a weU marked cingulum. The main cusp is bifid, as in Potamochoerus, and
resembles the corresponding tooth in that genus more than in Sus. There is also a
well developed posterior cusp, as in Potamochoerus.
FIRST molar: This tooth has been much damaged as the result of a fracture of the
mandible, which passes right through it. It is nevertheless clear that its maximum
length was about 25 mm., and a little greater than that of the 4th premolar, but much
less than that of the 3rd premolar. The maximum width was about 15 mm.
SECOND AND THIRD MOLARS: They Strongly resemble those of Sus. They show a
quincuncial arrangement of the main cusps, with a well developed talonid on the M3.
In both Mg and M3 the pillars of each pair meet along the median line, while the pairs
6
FOSSIL MAMMALS OF AFRICA No. 14
are separated from each other by a single median piUar. On Mg, there is a small
anterior, and slightly larger posterior, cingulum. The maximum length of M2 is
30 mm. and maximum width 21 mm. The talonid of Mg is not as long as the body
of the tooth and in this ratio it therefore resembles Stis and Potamochoerus and is
unlike Mesochoenis. It should be noted, however, that the talonid included two small,
more or less paired, pillars, which, with a little modification, might give rise to a
3rd pair of main pillars, such as seen in Mesochoerus. The length of Mg is 45 mm. and
the width 22 mm. The enamel of both these teeth is much pitted and corroded.
First Paratype. — This consists of a mandibular fragment (PI. i, fig. 4) containing
M2 and Mg. Morphologically they are in every way the same as the corresponding
teeth in the holotype and do not need further description. The measurements are:
M2 — maximum length 28 mm., maximum width 21 mm.; Mg — maximum length
51 mm., maximum width 23 mm.
The resemblance between these two teeth, and also those of the holotype, to the
corresponding teeth in Stis is so great that if other parts of the dentition, and particu-
larly Pg and P4, which are in the holotype, had not been found, the specimen would
have been attributed to the genus Sus. This fact emphasises the need for great
caution in using molar teeth of Pleistocene fossil pigs for diagnostic purposes, in the
absence of other evidence.
Second Paratype. — This is an upper third molar (PI. i, fig. 3), which was found
15 years after the original, within a few feet of the spot where the holotype was
discovered. There is reason to believe that it represents not only the same genus and
species but even the same individual. The tooth retains a small fragment of the
maxilla and the enamel in this case is well preserved, being neither pitted nor corroded
as in the other specimens. There is no trace of cement over the enamel. The tooth
is broadly triangular and the ratio of breadth to length is approximately the same as
that in Potamochoerus and rather greater than that in Sus scrofa; it is, however, less
than in the Indian fossil genera Sivachoerus, Tetraconodon and Conohyus. The length
of the talon is about one-third of the whole tooth. The tooth is wide anteriorly,
having a width over the^ anterior pair of pillars of 29 mm., while at the second pair
of pillars this has fallen to 24 mm., and the length across the middle of the talon is
only 16 mm. The tooth is composed of the normal two pairs of pillars, the com-
ponents of each pair meeting on the median line and with the pairs separated from
each other by a single median cone. In the valleys on either side of the median cone
are small cuspules and there is a well developed cingulum.
Discussion. — The enlarged Pg and P4 of the holotype invite comparison with the
three Indian genera Conohyus Pilgrim, Sivachoerus Pilgrim and Tetraconodon Falconer.
On the other hand, the lower molars suggest comparison with Potamochoerus and Sus
and the canine with Hylochoerus.
Nyanzachoerus kananiensis reveals a mixture of primitive and evolved characters.
Among the former are:
1. The verrucose type of canine;
2. The roots of the premolars — Pg has two roots and P4 three, whereas in Potamochoerus
and Sus both these teeth are only two-rooted. In the Indian genera Conohyus,
Sivachoerus dcRd^Setraconodon, both Pg and P4 have three roots;
EAST AFRICAN PLEISTOCENE SUIDAE
7
3-
4-
The size of Mi — it is longer than P^, although it is noticeably shorter than P3;
The enlargement of P3 and P4 in relation to the rest of the cheek teeth. The value
P X 100
of the index is greater than it is in Potamochoerus and Sus, but less
- 3
than in Conohyns and Tetraconodon (cf. Colbert, 1935). The value in SivacJioerus
has not been calculated from direct measurements, but the figures published by
Lydekker (1884) give an approximate value of 60 per cent, i.e., intermediate
between NyanzacJioerus and Conohyus. (Although some authors regard an increase
in the size of Ps_4as an advanced character, there seems to be little evidence for
such a view and it is here regarded as a primitive character sometimes seen in
Miocene forms of Suidae.)
Among the advanced characteristics are the following: —
1. The absence of Pi.
2. The reduction in size of P2.
In the Indian genera already referred to and in Sus, all four lower premolars are
retained. In Potamochoerus the first premolar is usually absent, but occasionally
found.
The systematic position of the genus NyanzacJioerus is at present uncertain.
There are close resemblances to Colbert’s group 3 of the Indian pigs and particularly
to Sivachoerus, but it would appear that the East African genus had already evolved
specialisations of its own, to some extent in the direction of Potamochoerus and
Mesochoerus.
Genus POTAMOCHOERUS Gray
Potamochoerus majus (Hopwood)
(Plate 2, figs. I, 2; Plate 3, figs. 1-7)
1934 Koiropotamus majus Hopwood, p. 547.
1942 Potamochoerus majus (Hopwood) Leakey, p. 183, pi. 61.
Diagnosis.- — “A Koiropotamus with very large upper tusks; three well-marked
areas of enamel on each tusk; the antero- and postero-superior areas 12-14 mm. wide,
inferior area up to 40 mm. wide near the base of the tusk. Main cusp of lower P4 more
definitely bifid than in Recent species.” Length of lower P2-M1 about 40 per cent
greater than in Recent species. (Hopwood, 1934).
Holotype. — (PI. 3, figs. 6, 7). Part of a left mandibular ramus with P3-M1 and
the alveolus for P2. (M. 14682, Brit. Mus. Palaeont. Dept.)
Paratypes. — Two upper tusks, probably of the same individual. (M. 14683,
Brit. Mus. Palaeont. Dept.).
Horizon. — The holotype (PI. 3, fig. 7) came from Bed IV at Olduvai Gorge and
the paratypes from Bed I. Both of these deposits can be dated to the Middle
Pleistocene. Bed I belongs to the lower part, i.e., the Kamasian Pluvial, while
8 FOSSIL MAMMALS OF AFRICA No. 14
Bed IV belongs to the upper part of the Middle Pleistocene and is attributed to the
Kanjeran Pluvial.
Additional Diagnostic Characters. — The upper and lower third molars carry
a thin layer of cement. There is a lack of constriction of the mandible of the kind
seen in the modern species between the canines and the third premolars. The lower
canine has a lateral groove comparable with that seen in Sus and the diastema is
relatively greater than in the modern species.
Notes. — The genus Potamochoerus is represented by a relatively small amount
of new material, although there are a few specimens which throw additional light upon
the species P. majus and give a reasonably good idea of the lower dentition of this
species. The upper dentition has been described and figured (Leakey, 1942) and
need not be repeated here. The specimens, which formed the basis of that account,
were Nos. F.3022-F.3024 of the Coryndon Memorial Museum (see PI. 3, figs, i, 2).
They have now been presented to the British Museum (Natural History) and are
registered as M. 17075-76. Other additional material, particularly a mandible found
at site B.K.II, Olduvai, in 1953, has also been presented to the British Museum
(Natural History).
The new specimens of P. majus are: —
A. The greater part of a mandible from site B.K.II, Olduvai Gorge, marked Old.
B.K.II, 1953/454. (M.17071, Brit. Mus. Palaeont. Dept.).
B. A well preserved lower 3rd molar from site F.L.K., Olduvai Gorge, from the top
of Bed I, collected in 1935. (M. 17074, Brit. Mus. Palaeont. Dept.).
C. An isolated lower canine tooth from Olduvai Gorge, site B.K.2, marked Old.
B.K.II, 1953/443. (M. 17073, Brit. Mus. Palaeont. Dept.).
D. An upper 3rd molar in a fragment of maxilla from site F.L.K., Olduvai. (M.17112,
Brit. Mus. Palaeont. Dept.).
Description of New Material. — A. the mandible from site b.k.ii, olduvai
GORGE. (Regd. No. M.17071; PI. 2, figs, i, 2). The mandible is well preserved and
was found during 1953 at the excavations at the Chellean I living-site. It is immature;
the third molars are neither fully formed nor completely erupted. The ascending
ramus on the right side has been broken off just behind M3 , while on the left side the
greater part of the corpus of the mandible, as well as the whole of the ascending
ramus, is missing, the fracture being just posterior to P3. The lower margin of the
corpus on the right side is damaged, but the anterior part of the jaw, including the
whole of the alveolar margin carrying the incisors and canines, is intact. On the right
side, the cheek teeth P3 to M3 inclusive are intact, while the socket and roots of P2 are
preserved, although the crown has been broken off. M3 has not yet reached the level
of the other teeth. The right canine is broken a little above the alveolar margin.
All six incisors are present and well preserved. The left canine is slightly damaged at
the tip; the left second premolar (which is missing on the right side) is fortunately
intact, while the third premolar is present, but damaged posteriorly.
When this mandible is compared with those of modern specimens of the genus
Potamochoerus, the first point noted is its relatively much greater size, while the
general similarity is good. Closer examination reveals certain fundamental differences
EAST AFRICAN PLEISTOCENE SUIDAE
9
which serve to help distinguish this species from the living representatives of the
group.*
In modern PotamocJioerus, the mandible exhibits a very marked constriction
between the canine teeth and the second premolars. This constriction is particularly
marked when the mandible is viewed from below. In Potamochoerus majus the constric-
tion is missing, and, morphologically, the appearance is much more like that seen in
Sus. On the other hand, a certain flattening of the lower margin of the corpus, which is
characteristic of modern Potamochoerus and absent in Sus, is present in the fossil
species. These differences between the fossil and the modern species can be clearly
seen in Plate 2.
The lack of constriction can be expressed numerically by taking the width at the
external walls of the alveolar margin at the canines and the minimum width of the
mandible behind the canines and expressing it in terms of a percentage, thus:
P. koiropotamus
P. majus
W idth of
alveoli at
canine
62 mm.
100 mm.
Minimum
width behind
canine
40 mm.
85 mm.
64-5
85
Another difference in morphology between Potamochoerus majus and the living
species is found in the body of the mandible in the region of the premolars. In the
living species there is a very marked lateral outward flaring of the bone of the jaw,
on either side, in the region of P4-Mi, which is completely absent in the fossil species.
At the posterior edge of the symphysis there are two strongly marked foramina,
very much as seen in the modern genera Phacochoerus and Hylochoerus, and very
dissimilar from the conditions seen in modern Potamochoerus or in Sus.
incisors: There are six lower incisors, as in Sus and in living species of Potamochoerus.
The two lateral incisors are markedly curved towards the median line and are rela-
tively bigger, in relation to the other incisors, than the corresponding lateral incisors
in either modern Sus or modern Potamochoerus. The width of the alveolar border
from the outer edge of one lateral incisor to the outer edge of the other is 78 .5 mm.,
compared with an average of 44 mm. in a number of specimens of the modern species
examined.
canines: The canine teeth are relatively small, but this is due to the immaturity of
the specimen. The anterior-posterior diameter of the canine at the alveolar margin
is 18.5 mm., and the maximum width at the alveolar margin 16.5 mm. The left
canine, which is the more complete, exhibits a very clear groove on either side —
a feature also seen in specimen M. 17073 (see below). Somewhat similar grooving is to
be found on canines of species of the genus Sus, but it is much less marked in living
species of Potamochoerus. In this respect, therefore, as in the structure of the jaw
behind the canines, Potamochoerus majus more closely resembles Sus than living
species of its own genus. The wear on the canines in this mandible extends right to
*Dr. Hopwood has suggested {in lit.) that the differences are sufficiently pronounced to justify separate
generic rank for P. majus, but I consider it wiser to await the discovery of a skull before creating a new
genus for this species.
10
FOSSIL MAMMALS OF AFRICA No. 14
the alveolar margin. A thin coat of enamel is present on both the buccal and lingual
aspects of the teeth, whereas posteriorly only dentine is visible. The canine teeth are
set in the mandible at a rather different angle from that seen in the living species of
Potamochoervis and are directed more forwardly and outwardly than in the living
species, where they tend to curve upwards and slightly backwards after leaving the
alveolar margin.
MOLAR-PREMOLAR SERIES! The exact length of the molar-premolar series of this
specimen cannot be given, since the hinder part of M3 is not fully developed. A figure
that may be regarded as accurate to within 2 mm. or 3 mm. is 135 mm., compared
with 104 mm. in the largest modern specimen that could be found. In this connection,
it must be remembered that the specimen is that of a juvenile and that the adult
length may have been greater — probably in the region of 145 mm. This corresponds
very well with the figure given in Hopwood’s diagnosis of a 40% greater size for
P. majus than for living species. P2_4 differ in no material respect from the corre-
sponding teeth in specimens of the living species, except in those characters already
pointed out by Hop wood: namely, that the main cusp of P4 is more markedly bifid
and that the posterior cusp of P3 is also more strongly developed.
In respect of M^ and Mg, the chief difference, apart from size, between the fossil
teeth and those of the living species is the greater development of the posterior
accessory pillars and cingulum. In particular is this true of Mg, where there is almost
a talonid behind the 2nd pair of pillars. These accessory pillars are of an unusual
character, for they project to form a heel from the inferior margin of the crown in
such a way that, when the crown is worn down, no trace of the talonid will remain.
The third molar of this specimen is not fully formed and no description of it can be
given, but two other specimens (see below), which are in a good state of preservation,
throw light on the nature of M3 of PotamocJioerus majus. The following are the
measurements of the individual teeth of the molar-premolar series of the specimen
under discussion:
Tooth
Maximum length
Maximum breadth
-
{mm.)
[mm.)
P2
10
5
P3
14
7
P4
18
13
M4
23
15
Mg
35
16
M3
46
22
The diastema between the canine and the second premolar is relatively longer than
in modern Potamochoerus.
B. A FRAGMENT OF A MANDIBLE FROM SITE F.L.K., BED I, OLDUVAI GORGE. (PI. 3, fig. 3)
This fragment contains a well-preserved M3 (M. 17074, Brit. Mus. Palaeont. Dept.).
The tooth is made up of two pairs of pillars, the respective elements of which meet at
the median line, the two pairs being separated from each other by a median pillar.
Anteriorly, there is a well marked cingulum, and posteriorly there is a talonid which
EAST AFRICAN PLEISTOCENE SUIDAE
II
is not as long as the body of the tooth, thus distinguishing it clearly from Mesochoerus.
The enamel is covered with a thin layer of cement. Maximum length, 46 mm.,
maximum breadth 22 mm.
C. A CANINE TOOTH FROM SITE B.K.II, OLDUVAI GORGE. (PI. 3, fig. 4)
This canine tooth (M. 17073, Brit. Mus. Palaeont. Dept.) is considerably larger
than the canines in the mandible already described.
In the immature specimen the wear on the posterior face of the tooth extends
to the alveolar margin. In order, therefore, to obtain measurements comparable with
those on the mandible, the measurements which follow have been taken at approxi-
mately the level where the wear-facet ends. At this point, the anterior-posterior
diameter is 26 mm. and the width is 18 mm. The tooth carries strongly marked
grooves on the buccal and lingual surfaces, similar to those already described. This
is characteristic of P. majus and is a feature in which this species differs from living
Potamochoerus, but resembles the genus Sus.
In the specimen under examination, the root of the tooth is damaged, but the
specimen, as preserved, has a maximum length (in a straight line) of 180*5
D. A FRAGMENT OF A MAXILLA FROM SITE F.L.K., OLDUVAI GORGE. (PI. 3, fig. 5)
This specimen is stated to have come from Bed II, whereas the lower molar (see
B above) from site F.L.K. came from Bed I (M.17112, Brit. Mus. Palaeont. Dept.).
The posterior end of this M3 is only just coming into wear. The enamel is thick
and there is a coating of cement on the outside. The crown is composed of two pairs
of lateral pillars, which are separated from each other by two small median pillars.
The enamel of the anterior pair of pillars meets in the median line, but the two pillars
of the second pair do not touch (as they do in the lower molars). Anteriorly, there is
a well developed cingulum. The talon length is less than the length of the body of
the tooth. The tooth is 43*5 mm. long, 22 mm. wide at the base of the crown and
18 mm. wide at the present occlusal surface. The height of the crown at the ist pair
of pillars is ii mm.
Remarks. — The figures given for the various teeth of Potamochoerus majus clearly
indicate its much greater size than the living species; this can also be seen in Plate 2,
where the mandible is figured next to an average sized modern Potamochoerus jaw.
Some of the morphological difficulties referred to in the text are also clearly visible
in the photograph. There can be no doubt that the species Potamochoerus majus
(Hopwood) is valid, and the only question that arises is whether the differences between
P. majus and P. koiropotamus are so great as to warrant setting up a new genus for
P. majus.
The differences may be summed up as follows;
1. Presence of cement on the third molars;
2. Lack of constriction behind the canines in the mandible;
3. Relatively greater length of the diastema;
4. Groove on the canine.
It should be noted that in Hopwood’s original description of P. majus he referred
two upper canine teeth to this species and treated them as paratypes. At the present
12
FOSSIL MAMMALS OF AFRICA No. 14
time there is no evidence to confirm that these two canines do, in fact, belong to the
genus Potamochoerus and there is some evidence which can be interpreted as suggesting
that they belong to Tapinochoeriis. In view of this, it is better to regard these two
canine teeth as only doubtfully representing the upper canine teeth of Potamochoerus
majus.
Potamochoerus koiropotamus Gray
(Plate 3, fig. 8)
The living species of Potamochoerus has been divided into many sub-species, but
so far no example of any form of the living species has been found fossil in any
deposits of Middle or Lower Pleistocene age in East Africa. In 1938, however, a well
fossilised fragment of pig jaw was found on the shores of Lake Eyassi in Tanganyika
Territory, during re-examination of the site where Dr. Kohl-Larsen recovered the
Eyassi human skull fragments. All the available evidence pointed to an Upper
Pleistocene date. This specimen clearl}/ represents the living species of Potamochoerus.
It is quite different from the Lower and Middle Pleistocene species, thus strengthening
the other evidence of the date of the Eyassi human skuU. The specimen consists of
a fragment of mandible, in which P4-M2 inclusive are well preserved, and parts of the
sockets of P and Mj (M. 17072, Brit. Mus. Palaeont. Dept.).
Neither in size nor morphology (see PI. 3, fig. 8) does this specimen differ from the
corresponding parts of the living species.
DISCUSSION OF THE GENUS POTAMOCHOERUS
Hopwood’s original description in 1934 of the new species Potamochoerus majus
of larger size than the existing species and with a notably more bifid lower 4th molar,
has been confirmed. The new material, which includes much of the lower dentition
as well as some upper, teeth, adds considerably to our knowledge of this species,
especially when taken in conjunction with the account of the upper dentition given
earlier (Leakey, 1942). Potamochoerus majus differs markedly from the living species
in certain morphological characteristics of its mandible and in certain respects un-
doubtedly approximates more closely to the genus Sus. This is particularly true of
the anterior part of the mandible where its similarity to Sus is marked. The dentition,
however, apart from the canines, quite definitely links this species with the genus
Potamochoerus and not with Sus. The rather specialised form of the talonid of the
lower second molars differs from that seen in both Sus and Potamochoerus and, later,
resembles the form seen in Tapinochoeriis. The premolars differ completely from those
of Sus and are, in all respects, typical of Potamochoerus. The cross-section of the lower
canine teeth is of Sus and not Potamochoerus form.
It may be said that Potamochoerus majus exhibits characteristics which are to
some extent intermediate between those of the two genera Sus and Potamochoerus
and when more complete material of Potamochoerus majus is obtained, the differences
may be sufficient to necessitate creating a new genus for its reception. On the other
hand, Potamochoerus might be treated as a sub-genus of Sus, with the species P. majus
in another sub-genus.
EAST AFRICAN PLEISTOCENE SUIDAE
13
Genus MESOCHOERUS Shaw & Cooke
(= Omochoerus Arambourg)
Diagnosis. — Suidae resembling Sus and Potamochoerus rather than Notochoerus
and Phacochoerus, but differing from the former in having lower third molars in which
the talon is always as long as, or longer than, the body of that tooth. The premolar
series is reduced to P2, P3 and P4 in the adults. The upper third molars have a talon
more complex than the talonid of the lower molars, and in the upper molars the
length of the talon may be slightly less than the main body of the tooth. In both
upper and lower third molars the paired cusps of the hrst, as well as of the second,
pair of pillars always meet along the median line and are not separated by a median
pillar as in Metridiochoerus, Tapinochoems and Notochoerus. The hrst and second
pairs of pillars are, however, separated by a median pillar, as in Sus and Potamochoerus.
The teeth are always strongly rooted, but may be either brachyodont or moderately
hypsodont. In some species the enamel bears traces of cement; in others it is free of
cement.
Mesochoerus paiceae (Broom)
1931 Notochoerus paiceae Broom, pp. 167-8, Text-hg. i.
1931 Hylochoerus : Hopwood, p. 133.
1941 Mesochoerus paiceae (Broom) Shaw & Cooke, p. 293, pi. 54, hgs. i, 2.
1949 Mesochoerus paiceae (Broom) : Cooke, p. 34, text-hgs. 18, 19.
Diagnosis. — No diagnosis of this species was given by Broom in 1931 or by
Shaw & Cooke in 1941. Cooke also described a further fragment of a mandible. No. 30
in the Fossil Collections of the Archaeological Survey, Johannesburg, which he
called a “neotype” of the species. This specimen, however, cannot be regarded as a
neotype in view of the fact that the original type had not been lost or destroyed.
Since the original material of the species is not available to me for study, I have not
attempted to give a specific diagnosis, but both genus and species were dehned by
Cooke in 1949.
Holotype. — Broom’s original specimen, which consists of a fragment of mandible
with a third molar in position. It is registered as M.M.K. 4088 in the MacGregor
Museum, Kimberley, South Africa.
Horizon. — The Vaal River gravels.
Locality. — Windsorton, in the Kimberley district.
The specimen was probably found in the Pleistocene deposits at Windsorton, which
have yielded Acheulean hand-axes, and is probably of Middle Pleistocene age. The
mandibular fragment which Cooke called a neotype came from gravels at Pniel, near
Berkeley West, South Africa, which are regarded by Cooke as of late Middle Pleisto-
cene age. The specimen was described and hgured by Cooke in 1949.
New Material. — The only material in the collection under review which can be
ascribed to Mesochoerus paiceae is a third upper molar in a very bad state of preser-
vation (M.14121, Brit. Mus. Palaeont. Dept.). It was collected by Dr. Dixey at Uraha
Hill in Nyasaland and provisionally regarded as a species of Hylochoerus (Hopwood,
1931).
14
FOSSIL MAMMALS OF AFRICA No. 14
Comparison with other Mesochoerus material leaves no doubt that it was wrongly
attributed to Hylochoerus. Its size and other characters suggest that it is probably
an upper molar of Mesochoerus paiceae. This specimen has a maximum length of
73-5 mm. and a maximum width of 38 mm. The whole crown is worn, so that the
dentine is exposed even in the pillars forming the talon; therefore, the height of the
crown cannot be given.
Hopwood {op. cit.) gave Upper Pliocene as the probable date of the Uraha Hill
material, but subsequent work in Africa suggests strongly that these deposits are not
of such great antiquity and a Middle Pleistocene date would appear to be more likely.
Mesochoerus heseloni Leakey
(Plate 4, figs. 1-5)
1943 (March)
1943
1943 (December)
1947
Mesochoerus heseloni Leakey, p. 55, pi. 19; pi. 20, figs. 13, 14a.
S'lis limnetes Hopwood : Leakey, p. 60.
Omochoerus pachygnathus Arambourg, p. 474, text-figs, i, 2.
Omochoerus heseloni (Leakey) Arambourg, p. 335, pi. 15;
pi. 16, figs. 1-3; pi. 18, fig. i; pi. 20, figs. 1-3, 6-8.
Diagnosis. — “A small Mesochoerus with third molars that are very low-crowned
in comparison with either of the previously described species, paiceae or olduvaiensis.
Roots of molars longer than height of crowns” (Leakey, 1943).
Syntypes. — Two fragments of mandible (PI. 4, figs, i, 2): originally belonging to
the Coryndon Museum (Nos. Omo 15 and 16), and now registered M. 17118a, h, Brit.
Mus. Palaeont. Dept., and a fragment of mandible (previously described as maxilla)
Regd. No. Omo 17, Coryndon Museum.
Horizon. — Lower Pleistocene, Kageran Pluvial (Villafranchian).
Locality. — Shungura, Omo Valley, Southern Abyssinia.
Remarks. — These specimens and others of the same species have been described
in detail (Leakey, 1943), and are not described again.
The nomenclatural history of this species is summarised above. The second and
third syntypes are identical with Arambourg’s material, and the differences between
the third molar of the first syntype and Arambourg’s specimens may well be inter-
preted as individual variations.
Arambourg (1947) described a number of specimens from the Omo Valley as
Omochoerus heseloni. These specimens undoubtedly belong to the same genus and
species as the original material described under the name of Mesochoerus heseloni and,
since Arambourg was working on better preserved material, his diagnosis may be
quoted here:
Hauteur
“Suine a dentition moins brachyodonte que celle du genre Sus (rapport y
I -■ i/t f H C' LV f
des molaires voisin de i). Dents depourvues de cement, a email epais, lisse, ne portant
que de tres fines stries horizontales au-dessus du collet. Incisives, tres robustes,
reduites a quatre chez les adultes. Canines robustes, emaillees, peu arquees. Serie
premolaire persistante, sauf la premiere. P* de type Sus\ P4 de type Potamochoerus.
EAST AFRICAN PLEISTOCENE SUIDAE
15
Troisieme arriere-molaire tres allongee par suite du developpement du talon qui
constitue un troisieme et, parfois a M3, un quatrieme lobe: talon de Mg au moins egal
en longueur aux deux premiers lobes; talon de M^ un peu plus court. Surface d’abrasion
des molaires presentant des replis d’email compliques du cote median des denticules
lateraux.”
This diagnosis, except for the reference to the canine teeth, which must be dis-
regarded since there is no proof that the canines in question belong with the other
material, is fuller and should stand in place of the original.
Since both collections from the Omo Valley — that made by Arambourg, and mine
from the Shungura sites — have been described and figured in detail, no purpose
would be served by repeating what has already been done, but certain points arising
from those descriptions will be referred to in the discussion of the genus as a whole.
It must, however, be noted here that the third syntype (Leakey, 1943) is not a
maxillary fragment with an upper third molar, but a fragment of mandible with
a lower third molar. For details of the structure of the upper third molars of this
species, Arambourg’s study must be consulted. It should also be noted that the
specimen from Shungura (PI. 4, fig. 5), which was referred (Leakey, 1943) to Sus
limnetes Hopwood, is not a tooth of Sus and is undoubtedly an upper third molar of
Mesochoerus heseloni.
The original type material (Leakey, 1943) is refigured here for comparison with
other Mesochoerus material, together with two other Shungura specimens (see PI. 4,
figs. 3, 4).
Mesochoerus limnetes (Hopwood)
(Plate 4, fig. 7)
1926a Sus limnetes Hopwood, p. 20, pi. 2, figs, ii, 12, text-hg. 6a.
1943 Sus limnetes Hopwood : Leakey, p. 60, pi. 20, fig. 146.
Hopwood (1926a:) described an upper third molar, and one or two other specimens
from the Kaiso Bone Bed, as Sus limnetes. Examination of the original specimen
strongly suggests that it is not attributable to the genus Sus but that it is a molar
tooth of a Mesochoerus.
The tooth, which is the holotype, has a much longer talon than is normal in either
Potamochoerus or Sus and is similar to that found in the Lower Pleisioceno, Mesochoerus
from the Omo deposits of comparable age. The crown is also low and, indeed, the
tooth is not easily distinguishable from upper molars of the Omo species.
It might be argued that Hopwood’s specimens from Kaiso ought to be treated as
belonging to the same species as the material described by Arambourg (1943) and
Leakey (1943) and that, since Sus limnetes has precedence as a specific name, limnetes
should replace heseloni. In view, however, of the evidence adduced of the unsatis-
factory nature of molar teeth for specific diagnosis, it would be wiser at the moment
to keep the Mesochoerus from Kaiso distinct, as Mesochoerus limnetes (Hopwood),
while recognising that when more extensive collections have been made in the Kaiso
deposits the synonymy of these two species may be established.
i6 FOSSIL MAMMALS OF AFRICA No. 14
The third upper molar from Shungura provisionally attributed to Sus limnetes in
(Leakey, 1943), belongs to Mesochoerus heseloni. Its resemblance to the upper molars
from Kaiso does not, of itself, justify regarding these two species as synonymous.
Holotype. — An upper third molar (M. 12614, Brit. Mus. Palaeont. Dept.).
Horizon. — Uppermost limit of the Villafranchian, closing stages of the Kageran
pluvial.
Locality. — Kaiso, Uganda.
Mesochoerus olduvaiensis Leakey
(Plates 5-7)
1942 Mesochoerus olduvaiensis Leakey, p. 179, pi. 60, top; text-fig. la, b.
Diagnosis. — A Mesochoerus with M^ much less hypsodont than in Mesochoerus
paiceae. The third molars are also narrower in relation to their length. The enamel
of the third molars has a thin layer of cement, more particularly in the valleys between
the pillars. In this respect, they differ from Mesochoerus heseloni, which has no cement
at all. This species is also markedly larger than Mesochoerus heseloni.
Holotype. — (Leakey, 1942). A broken fragment of the left side of a mandible
with damaged Mj, but with M2-3 intact. Formerly Coryndon Museum No. F.3666,
now registered M. 17090, Brit. Mus. Palaeont. Dept.)
Paratype. — A broken fragment of the right side of a mandible with damaged
ist molar and with 2nd and 3rd molars intact. Formerly Coryndon Museum
No. F.3023, now M. 17089, Brit. Mus. Palaeont. Dept.
Horizon and Locality. — Both the holotype and paratype were found in
Kamasian pluvial deposits at Olduvai Gorge referable to the lower part of the Middle
Pleistocene; the holotype in Bed II and the paratype in Bed I.
Description. — The holotype and paratype were figured and described in 1942
(Leakey, 1942) and the description need not be repeated. For purposes of comparison
both specimens are illustrated on PI. 5, figs, i, 2.
The collection now under examination contains a quantity of additional material
which is referable to Mesochoerus olduvaiensis and throws new light upon it. This
material is, therefore, discussed in some detail and additional specimens figured.
The most important of the new specimens is a large part of a mandible (Plate 6),
whose dentition is reasonably complete on the left side, with both canines preserved
as well as the incisors. This specimen is from site M.N.K. at Olduvai, from the junction
of Beds HI and IV. The horizon is Middle Pleistocene, at the close of the interpluvial
between the Kamasian and the Kanjeran (M. 17079, Brit. Mus. Palaeont. Dept.).
On the left side the mandible is relatively complete, except that the ascending
ramus has been broken away. In the anterior region, the whole of the symphysis is
well preserved and the alveolar margin with four incisors is intact. On the right side,
the mandible is broken off in front of the third premolar. In the laboratory, the bone
has been chipped away from the roots of the third molar to expose them for study.
The mandible is massive and exhibits the marked lateral swelling on the buccal side
in the region of the M3 which is so characteristic of the genus Mesochoerus (Leakey,
1942, 1943; Arambourg, 1943).
EAST AFRICAN PLEISTOCENE SUIDAE
17
The premolars have been reduced to two, P4 being present and P3 represented by
root sockets; Pg had been shed before death. The symphysial area is relatively narrow
and the arrangement of the canines is exactly as described by Arambourg (1947) for
the species M . Jiesdoni from Omo.
The anterior rim of the alveolar process carries four exceptionally massive incisors
and there are indications that lateral incisors of rudimentary character have recently
been lost. As the teeth in this specimen are not very worn, it seems likely that in
early adult life Mesochoerus had six incisors, which became reduced to four by the
early shedding of the lateral incisors. The development of the second incisors is
extraordinary and they are more massive than in all the other genera of pig examined.
The symphysial region is unusually long, partly due to a backward extension,
and the posterior end of the symphysis is more or less in line with the anterior end
of the third premolar. There is also a forward projection of the anterior part of the
jaw which carries the incisors. As a result of this lengthening, the diastema between
the canine and the P3 is unusually long. It cannot be measured exactly because of
damage to the border of the alveolus around the left canine, but was approximately
102 mm.
Although this specimen represents a relatively young individual, there is only the
barest trace of a root socket for Pg, which had been shed before the animal died.
In this respect, it would therefore appear that Mesochoerus olduvaiensis is more
specialised than Mesochoerus heseloni, since in the latter P2 was certainly present in
adult life.
incisors: These have been badly damaged and cannot be described in detail. They
are unusually massive, with a great anterior-posterior diameter. The four incisors
are narrow and the width from the outer edge of one second incisor across to the outer
edge of the other is only 59 mm.
canines: The canine teeth are very large and carry enamel on both the lingual and
buccal surfaces, which are slightly convex on either side. There is a very faint trace
of a lateral groove, which is much less developed than in Potamochoerus majus.
On the posterior face, the canines are only worn at the tips. The area of wear extends
for approximately 70 mm. from the tip, and the chord from the tip of the canine to
the alveolar margin is 142 mm. There is no sign of enamel on the posterior face of the
tooth below the level of wear. The whole root area of the right canine is exposed, so
that the length of the chord from the end of the root area to the extreme tip can be
measured: it is 236 mm.
PREMOLAR-MOLAR SERIES: The premolar-molar series is only preserved on the left side
of the mandible and consists of M3, M2, Mi, P4 and the socket of P3. The state of wear
indicates that the third molar had only recently been erupted and there are minor
differences between the dentition of this specimen from the junction of Beds III
and IV at Olduvai and more typical material from Beds I and II. It does not seem
justihable at present to separate this specimen from a slightly higher horizon than the
type material, from the species M. olduvaiensis , although that may become necessary
when more material is available. The length of the premolar-molar series, from the
i8 FOSSIL MAMMALS OF AFRICA No. 14
posterior end of M3 to the anterior end of P4, is 141 mm., compared with 13 1 mm. in
Shaw & Cooke’s South African specimen of M esochoenis paiceae.
P4 is very similar, in all respects, to other material of this species already described.
It is of the Potamochoerus and not of the Sus type, and its measurements are: length
i8'5 mm., maximum width 13-5 mm.
Ml is composed of two pairs of lateral cusps touching each other along the median
line, the pairs being separated from one another by one median cusp. There are small
accessory cusps anteriorly and posteriorly. The length is 22 mm. and the width
15 mm.
Mg consists of two pairs of lateral cusps, which touch along the median line and
are separated by a median pillar. There are small accessory pillars anteriorly and a
fairly well marked talonid posteriorly. The length is 27-5 mm. and the width 18 mm.
M3 is very long and, as in the case of some of the lower third molars from Bed II,
it is composed of four distinct pairs of lateral pillars, those of the first two pairs
touching each other along the median line, the pairs being separated by a single
median pillar. The other two pairs of pillars, which are really a development of
the talonid, differ in that the components of the lateral pairs are well separated from
each other by median pillars which thrust them apart. The total length of the tooth
is 71 mm. and the maximum width 22 mm. The crown height at the posterior end is
23 mm. and, since the posterior cusps are slightly worn, the original height was
probably a little greater. The tooth is well rooted, the roots of the talon being
26 mm. long and strongly formed. Thin cement covers the enamel of the teeth.
The great size of this jaw is shown by the distance of the alveolar margin between
the central incisors from the posterior margin of the ascending ramus, 416 mm., com-
pared with 303 mm. in a large Sus scrofa.
In addition to the, large jaw fragment described above, there is a considerable
quantity of new material from Olduvai Gorge, including hve large fragments con-
taining M3 and M^, one of which is M. 17080, Brit. Mus. Palaeont. Dept, (see PI. 5,
hg. 4), and one specimen carrying the series P^ to M3 (M. 17081, Brit. Mus. Palaeont.
Dept.) (see PI. 5, fig. 3). There are also three isolated lower third molars, one of which
is M. 17082 (see PI. 5, fig. 5).
For the upper dentition, additional material includes a fragment of skull with M^
and part of M^; two fragments of maxilla with the second and third molars, registered
respectively as M. 17077 and Old. S.H.K. II (see PI. 5, figs. 6, 7), and one fragment
of maxilla carrying a very worn third molar (PI. 7, hg. 2) found in association with an
upper canine tooth (PI. 7, hg. i) set in a maxillary fragment; these are marked Old.
B.K.II, Nos. iia and iib. There is also a fragment of maxilla carrying M^ M\ P^ P®
and the socket of P^; a maxillary fragment with M^; an isolated Mg, and two isolated
upper canine teeth, which are the same type as that associated with the M3 referred
to above. From Kanjera, there is a fragment of mandible carrying M^.
It does not seem necessary to describe the lower dentitions in this new material
in any great detail, since they correspond closely with the type material hgured and
described in 1942. The upper dentition must, however, be discussed, since it was
previously unknown.
EAST AFRICAN PLEISTOCENE SUIDAE
19
The following table sets out the measurements of third lower molars of Meso-
choeriis olduvaiensis.
Specimen
Maximum
Length
(mm.)
Maximum
Breadth
at 1st pair
of pillars
(mm.)
Maximum
Breadth
at 3rd pair
of pillars
(mm.)
Maximum')
Breadth j ,
Maximum r
Length J
Holotype (M. 17090)
67-5
25
23
37
Bed. IV. SI ... .
58
22?
19
37-9
Paratype (M. 17089)
65
24
21-5
36-9
M.N.K. III. 501
66
21
19
37
S.W.K. II. 500 ...
62
22
21
35-5
D.C. II. 2.6.35
62-5
—
—
—
G.H.-T.H. II. 3I-5.35
49
20
i8-5
40-9
Old. E.H.-B.F. (M.17081) .
53
—
—
—
Kanjera .....
60
22
19
36-6
Doug. K. I. (M. 17080)
66
22
20
37
Old. I. 1931 ....
55
22
21
40
M.15858
66
22
19
37
V.E.K. I
56
—
19
—
55
22
21
40
B.K. II. 9/52 ....
69
—
21
—
For comparison with the table given above, the following are the corresponding
measurements of Mesochoerus paiceae from South Africa.*
Specimen
Maximum
Length
(mm.)
Maximum
Breadth
at ist pair
of pillars
(mm.)
Maximum
Breadth
at 3rd pair
of pillars
(mm.)
Maximum'
Breadth
Maximum
Length
s Index
Type
68
23
22
32-3
Specimen described by Cooke, 1949
68
22
20
32-3
*Singer & Keen described a new Mesochoerus {M. lategani) from Hopefield, South Africa, in 1955.
The teeth resemble those of M. olduvaiensis, but are longer and narrower.
20
FOSSIL MAMMALS OF AFRICA No. 14
The following are the corresponding measurements of lower third molars of
Mesochoerus Jieseloni, from the Lower Pleistocene of the Omo Valley:
Specimen
Maximum
Length
(mm.)
Maximum
Breadth
at 1st pair
of piUars
(mm.)
Maximum
Breadth
at 3rd pair
of pillars
(mm.)
3Iaximum3
Breadth 1 t j
Maximum f
Length J
ist syntype (M. 17118a)
49
21
18
367
2nd syntype (M. 17118b)
55
22
19
40
F.2196
54
20
i8-5
37
F.2195
56
21
18
37-5
F.2194
57
21
17
37
^ 302 .
52
20
—
38
304 .
56
24
—
42-8
Arambourg’s ^
specimens
303 •
49-6
20-6
—
41-5
840
61
24
—
39-3
^ 320 .
53
19
—
35-8
From the above tables, it will be seen that the length-breadth index of Mesochoerus
olduvaiensis from the Middle Pleistocene ranges from 35-5 to 40-9, whereas that of
Mesochoerus heseloni from the Omo beds ranges from 35-8 to 42-8. Against this, the
material attributed to Mesochoerus paiceae of South Africa gives an index of 32-3 in
both cases, although the two specimens were obtained at widely different sites.
It would thus appear that the length-breadth index of the third lower molars will not
serve to distinguish the Lower and Middle Pleistocene species of M esochoerus in East
Africa. The relative height of the crowns, however, and the fact that the Middle
Pleistocene species has cement over the enamel whereas the Omo Lower Pleistocene
species has none, are diagnostic characters.
Among the new material there are four specimens with well-preserved lower
second molars. These compare so well with the original type material that nothing
except the measurements need be given. They are:
Specimen
Maximum Length
(mm.)
Maximum Breadth
at the posterior
pair of pillars
(mm.)
M. 17080 (Doug. K.i.) .
24-5
19-5
M.17081 (Old. E.H.-B.F.) .
27
19
Old. 1. 31 ....
27
19
Old. D.C. II. 35
30
20-5
EAST AFRICAN PLEISTOCENE SUIDAE
21
It should be noted that in the Ma of Mesochoerus the length of the tooth decreases
with increasing wear, whereas the length of M3 increases with advancing age. This is
because the talonid of Ma extends backwards from the base of the crown as a marked
heel and diminishes with progressive wear until, in the hnal stages of wear, it has
completely disappeared. In the specimens which appear in the above table, that
from site Doug. K.i. is a very worn tooth, whereas that from D.C.II is a tooth only
recently erupted.
A specimen amongst the new material (M. 17081) exhibits Mi as well as P4, neither
of which had previously been described in Mesochoerus olduvaiensis. Mi is very worn
and also slightly damaged, but its approximate dimensions are; length 18 mm.,
width 14 mm. (?). The P^ is almost identical with that of M esochoerus heseloni from
the Lower Pleistocene and is of Potamochoerus rather than Sus type. Its measure-
ments are: length 17-5 mm., width 13 mm. The length from P^ to M^ is 114-5 mm.,
compared with the corresponding measurement of 112-5 mm. in the holotype of
Mesochoerus heseloni.
In the height and length of the crown, this specimen is nearer to M. heseloni than
to M. olduvaiensis , but in the characters of the roots and of the cement it is closer
to the latter species, with which it is included for the present.
Upper Dentition. — The upper dentition of this species was previously unknown,
but it is represented by a number of specimens in the present collection. The following
details are, therefore, of some importance in obtaining a more complete picture of the
species.
A. A FRAGMENT OF A MAXILLA, SITE S.H.K. II, OLDUVAI GORGE (PI. 5, fig. 7)
This fragment of a maxilla, marked 53/245, has M^ in full wear and M^ partially
erupted, while the sockets of M^ and P^ are also preserved. It was found in association
with a very damaged fragment of mandible, marked Old. S.H.K. II, 53/246, which is
entirely characteristic of M esochoerus olduvaiensis in its very greatly enlarged incisors,
the cross-section of the lower canine and the position in which this tooth is set in the
jaw.
M^ in this maxilla resembles very closely M2 of this species, being composed of two
pairs of lateral cusps, the elements of which meet in a median line and the pairs are
separated by a single median cusp. Both anteriorly and posteriorly there are acces-
sory cusps and, in particular, the posterior cusps project to form a heel, so that in
wear they would tend to disappear. The length of M^ in this case is 31-5 mm. and the
width 21 mm. The upper third molar is composed of two main pairs of pillars, the
elements of which are contiguous along the median line, while the two pairs are
separated from each other by a central pillar; there is also a well-marked talon, the
elements of which, in advanced wear, might easily appear as two further pairs of
pillars. The enamel is covered with cement. The height of the crown of the unworn
talon of this tooth is 27 mm.; the greatest length of the tooth is 59 mm. and the
greatest width 24 mm. The roots are strongly developed and longer than the height
of the crowns, although the^^ still have open pulp cavities at the base.
B. A FRAGMENT OF A MAXILLA, SURFACE OF BED III, OLDUVAI GORGE (PI. 5, fig. 6)
This specimen (M. 17077, Brit. Mus. Palaeont. Dept.) carries M'*, M^ and the sockets
of Mb M^ is just reaching full wear, while M^ is not fully erupted. The maximum
22
FOSSIL MAMMALS OF AFRICA No. 14
measurements of this specimen are: length 53 mm. and width 22 mm. The maximum
measurements of M^ are: length 29-5 mm. and width 21 mm.
C. A FRAGMENT OF A MAXILLA AND ASSOCIATED CANINE TOOTH, SITE B.K.II, OLDUVAI
GORGE (PI. 7, figs. I, 2)
Since the two fragments do not fit together, although found associated, it is not
possible to be completely certain that they represent parts of the same individual,
or even the same species, but the association was of such a nature that little doubt
exists. The third upper molar is that of an old individual and is very worn; its
measurements are: length 62 mm., width 26 mm.
In this advanced state of wear (almost to the base of the crown) the median pillar
separating the first pair of pillars from the second pair is seen to have wedged back-
wards, so that the second pair does not touch along the median line. In all other
respects, it is a typical M^ of Mesochoerus and the unusual condition is undoubtedly due
to the advanced age of the individual.
The associated canine tooth is very large and of the Phacochoerus type rather than
of Sus and Potamochoerus. If the association of the canine with the third molar is
not fortuitous, its resemblance to Phacochoerus is of special interest, since in so many
other characters Mesochoertis approximates more closely to the latter group. This
tooth is in its bony socket, but has slipped forward slightly after death, so that it now
projects further from the alveolar rim than in life. A line of slight discolouration
marks the original position in the socket, indicating that the displacement is about
36 mm. forwards. The tooth carries no visible trace of enamel on any of its three
faces. The total length along the convexity is 372 mm. and the measurement across
the chord is approximately 283 mm. The maximum thickness from the buccal to
the lingual side, at the point where the tooth originally emerged from the alveolus, is
37 mm. and at the 'same point its anterior-posterior diameter is 60 mm.
The wear on the anterior face of the tooth is situated part of the way down,
starting at a distance of 160 mm. from the tip and extending down towards the base
for 141 mm. At the lower end of the tooth, there is a distinct groove or valley on
both the lingual and buccal aspects, but each groove fades out and disappears about
half-way along the length of the specimen. On the anterior face of the teeth, there is
also a median groove for a short distance, but this disappears in the region where the
wear is first apparent.
An important feature of this specimen is that the canine tooth is set in an unusu.d
plane relative to the palate. The fragment of maxilla carries on its lower surface
a clear trace of a part of the palatal groove and, when this is orientated in its correct
position, the bony socket carrying the root of the canine has a position unlike that
seen in any other pig: it is rotated through approximately 90° from the normal
position.
The position of the palatal groove, in relation to the socket of the canine, indicates
that the upper canine faced markedly forwards, a feature already noted in relation
to the lower canines of this species. The specimen suggests that, when the complete
skull of Mesochoerus olduvaiensis is discovered, it is likely to have a number of unusual
features.
EAST AFRICAN PLEISTOCENE SUIDAE
23
Mesochoerus grabhami (Hopwood)
(Plate 4, fig. 6)
1929 HylocJioerus grabhami Hopwood, p. 289.
1930 Rylochoer us grabhami Hopwood: Bouet & Neuville, p. 299, text-fig. 74.
1943 Omochoerus grabhami (Hopwood) Arambourg, p. 475.
Hopwood (1929) described a specimen obtained from Kosti, on the White Nile
100 miles south of Khartoum in the Sudan, under the name of Hylochoerus grabhami
■sp. nov. (Brit. Mus. Palaeont. Dept., Regd. No. M. 13253). Re-examination of this
specimen leaves very little doubt that it represents a Mesochoerus rather than a
Hylochoerus and that it should be regarded as a Sudanese representative of this group
of pigs.
The tooth (PI. 4, hg. 6) is a third molar, whose anterior part is broken off. It is
uncertain whether only the anterior pair of pillars has been lost, or whether two pairs
have been lost. In either case the talonid is much longer than the main body of the
tooth. Subsidiary pairs of pillars have developed from the cusps of the talonid in
typical Mesochoerus fashion, with a line of m.edian pillars separating the laterals.
A further point in which the specimen differs from Hylochoerus is that the lateral
pillars are longer than wide, whereas in Hylochoerus they are much wider than long.
Moreover, in the third molars of Hylochoerus the opposing enamel ridges wear
deeply into the dentine between the pairs of pillars, making smooth wear-facets in
the valleys between the pillars, along either side of the tooth. In all respects, the
tooth from Kosti fits in very well with Mesochoerus, but it is impossible to link it
with any particular species from East Africa. In view of the geographical position of
the find, it seems safest at present to assume that it represents a distinct species.
Horizon. — The geological horizon of the specimen is not determinable on the
present evidence.
DISCUSSION OF THE GENUS MESOCHOERUS
The genus Mesochoerus was founded by Shaw & Cooke (1941) in their paper on
fossil pig remains from the Vaal River gravels. The type-species is Notochoerus paiceae
Broom, which Broom (1931) did not differentiate from his genus Notochoerus, although
he had stressed the fact that this species might later have to be given generic rank.
In coming to the conclusion that a new genus must be recognised, the two authors
were influenced by an additional specimen which had become available, in which
there was an unworn M3. This showed that, although the tooth was strongly rooted
and quite unlike those of the Phacochoerus and Notochoerus, it was, nevertheless,
markedly hypsodont.
In 1942 certain specimens from Olduvai Gorge were attributed to the new genus
under the name of Mesochoerus olduvaiensis (Leakey, 1942): this new species differed
from M. paiceae in being considerably less hypsodont, as well as in certain other
characters. In 1943 another species of Mesochoerus [M. heseloni) was based upon
Lower Pleistocene material from Shungura, in the Omo Valley, Abyssinia (Leakey,
1943). This species differs from those from Olduvai and South Africa in being just
brachyodont and in lacking any trace of cement over the enamel; yet in all other
24 FOSSIL MAMMALS OF AFRICA No. 14
respects it appears to fit Mesochoerus. Arambourg, also in 1943, described a new
genus of Suidae from the Lower Pleistocene deposits of the Omo Valley as
Omochoents pachygnathus (Arambourg, 1943). This was in a preliminary note.
In 1947 he recognised that his material was identical with M. Jieseloni, but used the
specihc name 0. Jieseloni because he thought that the Omo species should not be
included in the genus Mesochoerus, which, however, he recognised as valid. He based
his view on the facts that the material from Omo differed from both Mesochoerus
Jieseloni and Mesochoerus paiceae in having no cement on the enamel and in being just
within the brachyodont range.
There is now available a very considerable series of specimens of the Lower
Pleistocene species M. Jieseloni and of the Middle Pleistocene species jM. olduvaiensis,
while the South African species M. paiceae is also rather better known than hitherto.
When examples of these three species are examined side by side, it is at once obvious
that, morphologically, they represent a closely allied series, which, however, starts by
being very slightly brachyodont and becomes hypsodont.
The series indicates clearly that there has been progressive specialisation, but
neither the increasing hypsodonty, nor the absence of cement in the earlier and less
specialised group, justihes giving the Omo form separate generic rank. Arambourg’s
genus Omochoerus has, therefore, been relegated to the synonymy of Mesochoerus.
No complete skull of Mesochoerus is yet available and there is only one relatively
complete lower jaw (M. 17079, Brit. Mus. Palaeont. Dept.). It is possible that, when
well-preserved skulls of all the species are obtained, a further revision may have to be
undertaken, but it is likely to be in the direction of still further reducing the number
of species.
Although there is no absolute certainty that the upper canines here described
belong to Mesochoeyus, the apparent association of the fragment of a maxilla, con-
taining the upper third molar, with that carrying the upper canine strongly suggests
that this is the case. Although this association is, therefore, subject to confirmation,
it should be noted that it is now very doubtful whether the upper canines, which were
attributed to Mesochoerus (= Omochoerus) by Arambourg (1947), do in fact belong to
this genus. The Omo deposit also contained much fossil material of the genus
N otochoerus and it would appear more likely that the upper canines are attributable
to the latter genus. It must also be pointed out that Arambourg (1947, pi. 20, fig. 7)
illustrates a fragment of the mandible of Mesochoerus (= Omochoerus) Jieseloni)
I recently examined the original of this specimen and noted that the left canine does
not belong to the specimen at all. It has been inverted and the anterior end is facing
backwards, while the root-end projects from the alveolus; and whereas the broken
section of the right canine is typical Mesochoerus lower canine, with slightly biconvex
section to the labial and buccal aspects, the left canine is an entirely different type
and clearly has been erroneously inserted into the specimen and set on to it with
plaster.
The genus Mesochoerus is of particular interest because it has characters which
connect it with so many other genera of pigs. Its P4 resembles very closely that of
Potamochoerus, whereas its P'‘ is more reminiscent of Sus) its upper canines recall
those of Phacochoerus, but the lower canines resemble much more closely those of
Plylochoerus.
EAST AFRICAN PLEISTOCENE SUIDAE
25
The lower molars in the early Pleistocene form M. heseloni suggest a recent
evolutionary trend away from Potamochoenis and Sus, while the most specialised
and evolved species, M. paiceae from South Africa, suggests in its increasing hypso-
donty a trend towards Notochoerus and Phacochoerus. On the other hand, the unusual
forward direction of the lower canines, seen in both the Olduvai and Omo species, as
well as the remarkable orientation of the upper canines in the former species, confirm
that it is a group which had clearly been separated from other better known genera.
Recently, a new species of pig has been described by Ennouchi (1954) from the
Upper Villafranchian deposits of Morocco as Omochoerus maroccanus, but I suspect
that it is a Mesochoenis.
Genus METRIDIOCHOERUS Hopwood
Metridiochoerus andrewsi Hopwood
(Plate 8, figs. I, 2)
1926 Metridiochoerus andrewsi Hopwood, p. 267, text-fig. i.
Diagnosis. — “Pigs with rooted, hypsodont, third molars. Enamel-pattern
complicated, intermediate between Hylochoerus and Phacochoerus, the degree of
folding being such that very little more would be necessary to cause the figures to
split up into separate pillars. Talon, and probably the whole tooth, with an enamel-
pattern of numerous small rings in the early stages of wear” (Hopwood, loc. cit.).
Material. — A third upper molar; holotype registered M. 12805, Brit. Mus.
Palaeont. Dept. (PI. 8, fig. i). Two talons of third molars (both upper teeth?), para-
types, M. 12805a & h, Brit. Mus. Palaeont. Dept.
New Material. — Specimens clearly attributable to the genus Metridiochoerus are
rare in the collection, but there is a fragment of a maxilla from Kagua, near Homa
Mountain (PI. 8, fig. 2), which is unquestionably attributable to Metridiochoerus
andrewsi. This new specimen is from the same area as that covered by Dr. Oswald
in 1911 and, since the only locality which he gives is /'near Homa Mountain”, it is
possible that his specimen, which formed the holotype, may have come from the same
place. The deposits at Kagua belong definitely to the Middle Pleistocene and corres-
pond in general to those of Olduvai.
Horizon. — The available evidence suggests that the geological horizon of
Metridiochoerus andrewsi is Middle Pleistocene. In addition to the fragment of a
maxiUa mentioned above, there is also a fragment of a third molar from Olduvai,
which is of the Metridiochoerus type, and two third molar fragments from Kanjera.
Description of the Fragment of a Maxilla (M. 15880, Brit. Mus. Palaeont.
Dept.) (PI. 8, fig. 2). — In order to study the roots of this specimen, the bone
has been cut away from the roots of M® on one side. Their condition is very similar
to that seen in N otochoerus (see below) and quite unlike that of Phacochoerus or
Tapinochoerus. The wear of M^ is slight, while that of M^ is so advanced that only a
small stump remains. It is clear that before long the latter would have completely
26
FOSSIL MAMMALS OF AFRICA No. 14
disappeared and that the dentition would have been reduced to M^'^. In this respect,
Metridiochoerus closely resembles Phacochoerus and, to a lesser extent, Notochoerus.
It is not possible to give any measurements of M\ but it was clearly not large.
M^ is well preserved; it is composed of two pairs of lateral pillars with a very complex
enamel pattern, the pairs being separated from each other by a single median pillar.
In the present specimen, the relatively advanced state of wear of M^ resulted in the
enamel of the two anterior pillars forming one long and continuous band with complex
folding, with two smaller island pillars at the anterior end. Similarly, the enamel
pattern of the posterior pair of pillars has run together to form a continuous circuit,
within which there are five small, separate island pillars. In this character, the
second molar is similar to worn upper molars of Notochoerus. The third upper molar
corresponds in every way to the holotype and, like it, differs from all known upper
molars of Notochoerus in having a talon which is composed of a very large number of
small, circular and sub-circular pillars. In the holotype, there are 22 of these and
in the present specimen 18. It is this breaking up of the components of the talon
that characterises the genus Metridiochoerus and makes it easy to distinguish from
other fossil pigs. The following are the measurements of the second and third molars
of the specimens just described:
Third Molar
Second Molar
Specimen
Maximum
Maximum
Maximum
Maximum
Length
Breadth
Length
Breadth
(mm.)
(mm.)
M. 15880
62
20
28-5
20
M. 12805 • • . •
H
00
—
—
A small fragment of a talon from Bed I, Olduvai, is undoubtedly attributable to
Metridiochoerus and is the only specimen of the genus so far recorded from the
deposits of the Gorge. There are also two fragmentary specimens from the Kanjera
region, near Floma Mountain.
Since only the upper dentition of Metridiochoerus is known, it seems preferable
to retain its generic rank, but it is possible that, when this genus is known from more
complete material and from associated upper and lower dentitions, it may become
necessary to transfer it to the genus Notochoerus and to regard it as a very aberrant
and over-specialised form.
Metridiochoerus pygmaeus sp. nov.
(Plate 8, fig. 3)
Diagnosis. — A species of Metridiochoerus, in which the third upper molar has only
one pair of main pillars behind which is a talon of typical Metridiochoerus form
composed of numerous small pillars. The enamel of the tooth is covered by a thin
layer of cement.
EAST AFRICAN PLEISTOCENE SUIDAE
27
Holotype. — An upper third molar from Kanam Central. (M. 15932, Brit. Mus.
Palaeont. Dept.).
Horizon. — Lower Pleistocene (Kageran pluvial).
Description. — An upper third molar, composed of a pair of anterior pillars which
meet on the median line, behind which is a group of small pillars of the character-
istic Metridiochoerus form. In general appearance, the tooth pattern closely resembles
Metridiochoerus andrewsi, except for the lack of one pair of pillars. The posterior end
of the talon is only just coming into wear and the crown is very much lower than in
Metridiochoerus andrewsi. There is a layer of very thin cement over the enamel.
The maximum measurements of the tooth are: length 40 mm., width 24 mm., and
height at the last unworn pillar 19 mm. (crown only) . The occlusal length is 35 mm.
and occlusal width at front 19 mm.
DISCUSSION OF THE GENUS METRIDIOCHOERUS
The most characteristic feature of the genus Metridiochoerus is the breaking up
of the talon of the upper third molars into a very large number of small circular and
sub-circular pillars, a character which differentiates it completely from Notochoerus
and other allied forms. Unfortunately this generic character has not been sufficiently
appreciated by some authors and, in consequence, Arambourg (1947) ascribed to the
genus Metridiochoerus a considerable quantity of fossils from Omo which, in fact, are
in no way connected with this genus. I have examined this material in Paris and am
certain that none of it can be properly assigned to Metridiochoerus. Fortunatel}^
Arambourg’s material includes a well-preserved jaw, as well as a number of upper
molars, and there can be no doubt that the Omo fossils should be attributed to
Pronotochoerus jacksoni.
The rareness of Metridiochoerus material in the otherwise large collections of fossil
Suidae from East Africa suggests that it may have had a different ecological back-
ground from that of the other genera, which are so plentiful. As already noted,
Metridiochoerus appears to resemble N otochoer^is more than any other genus and a
time may come when it will be necessary to suppress Metridiochoerus in favour of
Notochoerus, which has priority. It would be unwise to do this at the moment, since
resemblances in the dentition in the Suidae do not always indicate resemblances in
the general skull morphology ,and the skull of Metridiochoerus may prove to be very
different from that of Notochoerus.
Genus PRONOTOCHOERUS Leakey
Diagnosis. — Suidae with long-rooted, slightly hypsodont upper and lower third
molars, in which the crown is clearly differentiated from the roots. Roots usually
longer than the height of the unworn pillars of the crown. Roots of talon and talonid
strongly developed and fused. Enamel pattern of lower third molars consists of pairs
of lateral pillars, separated down the median line by a row of smaller pillars, as in
Notochoerus. Premolars reduced in adult specimens to P4. In some cases, P4 and
even Mj may be completely missing. Incisors in adult life reduced to four.
Type Species. — Pronotochoerus jacksoni Leakey.
28 FOSSIL MAMMALS OF AFRICA No. 14
Pronotochoerus jacksoni Leakey
(Plate 8, figs. 4-6)
1943 Pro-notochoerus jacksoni Leakey, p. 53, pi. 18, figs. 9, 10.
1947 Meiridiochoerus andrewsi Hopwood : Arambourg, p. 34, pi. 16,
fig. 4; p]. 17, figs. 1-3; pi. 18, figs. 2, 3, 5; text-figs. 37-41-
Holotype. — A lower left third molar in a fragment of mandible (formerly Coryn-
don Museum, Omo 12, now registered as M. 17083, Brit. Mus. Palaeont. Dept.).
Paratype. — A fragment of mandible with damaged third and second molars, as
well as fragments of the first molar and socket of fourth premolar. Coryndon Museum.
Regd. No. F.2190, Omo 13.
Horizon. — Lower Pleistocene, Kageran pluvial.
Locality. — Shungura, Omo River, Abyssinia.
Description. — type and paratype. These were described and figured in 1943
and need not be discussed in detail here. The holotype is, however, figured on PI. 8,
figs. 4, 5 for purposes of comparison.
ADDITIONAL MATERIAL. — Amongst the new material now available is a fragment
of mandible from the Marsabit Road site in North Kenya. This consists of a lower
third molar in a broken fragment of mandible, which in all respects resembles the type
material. Its measurements are: maximum length 56-5 mm., maximum width 21 mm.
The specimen is in the Coryndon Museum (see PI. 8, fig. 6).
As already indicated, the collection in Paris includes a number of specimens
which should correctly be attributed to Pronotochoerus jacksoni. These include a well-
preserved anterior part of the lower jaw. Therefore, for further data concerning the
upper and lower dentition of the species P. jacksoni, Arambourg’s account (1947) of
what he called Meiridiochoerus andrewsi should be consulted. In it he gave informa-
tion about the upper dentition and illustrated clearly the upper third molars of this
species on pi. 18, figs. 3, 3« and text-fig. 38.
Protjotochoerus iiyan'zae sp. nov.
(Plate 9, figs. 1-4)
Diagnosis. — A Pronotochoerus considerably larger than Pronotochoerus jacksoni
and with a more developed talonid of the lower third molar. The enamel pattern
resembles that seen in Notochoerus, from which genus it differs by being much less
hypsodont and by the greater development of its roots. The symphysial length is
relatively greater than in P. jacksoni.
Holotype. — The left side of a mandible containing M3, M^, a very much damaged
Ml and a rudimentary P4. The root of the canine is preserved in its socket, as well as
the left median incisor and the socket of incisor 2 (M.15941, Brit. Mus. Palaeont.
Dept.).
Horizon. — Early Middle Pleistocene. The early part of the Kamasian pluvial.
Locality. — Rawi, site 5, near Homa Mountain.
EAST AFRICAN PLEISTOCENE SUIDAE
29
Description. — The left half of the mandible (PI. 9, fig. i) is relatively complete,
except for the ascending ramus, which has been broken off at about 100 mm. behind
M3 and at approximately the point where the angle of the jaw turns upwards. The
length of the fragment, as preserved, from a point on the alveolar margin at the
symphysis to the fracture of the mandible at the posterior angle is 352 mm. The
total length was, therefore, probably somewhat greater. The bone on the lingual face
has been chipped away in the region of the third molar to expose the roots for study
(see PI. 9, fig. 4). The most noticeable feature of the specimen is the great length of
the symphysis from the anterior alveolar margin to the posterior point, which is
1 18 mm., compared \vith a measurement of only 79 mm. in the species P. jacksoni.
The marked flattening of the whole of the anterior portion of the jaw on either side
of the symphysis is also a distinguishing feature of the new species, the line from the
anterior alveolar margin to the posterior margin of the symphysis being only very
slightly convex on the labial aspect. The anterior margin of the mandible is wide and
the distance between the symphysial line and the alveolus of the canine is 62 mm.
The diastema, from the posterior margin of the canine to the anterior edge of the
fourth premolar, is 83 mm. The length of P4 to M3 is 117 mm.
P4 is a very small tooth, compared with the corresponding tooth in MesocJioerus
or Potamochoerus. It measures only 12 mm. long and 10 mm. wide, the greatest
width being at the posterior end. It is much less worn than Mj, which is worn down
to the roots and, when death occurred, was in process of being shed. Mi cannot be
measured. At its posterior margin. Mg underhangs the anterior edge of M3, so that its
length cannot be measured exactly; it is approximately 24 mm. long and is 17 mm.
wide. Owing to the advanced state of wear, the enamel pattern cannot be seen.
M3 is composed of the three pairs of lateral pillars and a talonid. Owing to the
advanced state of wear, the enamel of the anterior pair of pillars has run together and,
in part, joined up with the enamel of the buccal element of the second pair of pillais,
as well as with the median pillar which separated the first from the second pairs. The
length of the tooth is 60 mm. and the width 19 mm. The removal of the bone to
expose the roots reveals the characteristic Pronotodioems pattern, identical in all
respects with that seen in the type species. There is also the curious backward pro-
jection of a heel at the posterior end of the talonid (compare PI. 8, fig. 5 and PL 9,
fig. 4). The single incisor that is preserved indicates that these teeth were much
reduced, compared with those of MesocJioerus or Potamochoerus, while the stump of
the canine also suggests a relatively small tooth. In so far as can be seen from the
stump, the labial and buccal aspects of the canine were more convex than in
Mesochoerus or Potamochoerus, had no groove and carried a fairly thick enamel. The
specimen is illustrated on Plate 9, fig. i, where it is compared with a jaw of a modern
Phacochoeriis. Plate 9, figs. 3, 4 show the details of the crowns and the roots of the
third molars.
DISCUSSION OF THE GENUS PRONOTOCHOERUS
The genus Pronotochoerus is confined, so far as is at present known, to the Lower
Pleistocene and the early part of the Middle Pleistocene. The species P. jacksoni
comes from the Omo deposits, where it is very common; these beds were laid down
during the Kageran pluvial. The species P. nyanzae comes from the lower Rawi Beds,
30 FOSSIL MAMMALS OF AFRICA No. 14
formed during the early part of the Kamasian pluvial period. It seems likely that the
species P. nyanzae represents a final specialisation before extinction. Pronotochoerus
seems to be closely allied to Notochoerus and, more remotely, to Tapinochoerus and
Metridiochoerus. It would seem probable that Pronotochoerus, as it occurs in the
Lower Pleistocene deposits of Omo and as represented by the species P. jackso7ii, may
well represent a Pleistocene survival of a generalised pig from which the more specialised
Notochoerus, Metridiochoerus and Tapinochoerus, as well as possibly Phacochoerus,
could all have evolved. The persistence into the Lower Pleistocene of a supposed
ancestral Pliocene form, in association with one or more of its later derivatives, is
paralleled by other examples of East African fauna, such as hipparionids, which per-
sisted until they were contemporary with many species of Equus, and the archaic
Dinoiherium and Stegodon found in deposits contemporary with those of more
advanced elephants.
Pronotochoerus shows a gradual change from a long-rooted and relatively low-
crowned type towards the more hypsodont and shorter-rooted Notochoerus. In the
development of the posterior roots on the talonid of the third molars, there is evidence
of a tendency towards the type of extreme hypsodonty seen in Tapinochoerus and it
would only require the gradual disappearance of the line of demarcation between the
crown and the roots to make them resemble Tapinochoerus, with the crown and root
elements fused into one.
The earlier confusion between Metridiochoerus and Pronotochoerus is unfortunate,
since it may obscure the distinctive characters of these two genera. Not only is the
pattern of the crown wholly different, at least in the upper third molars (we do not
yet know the lower third molars of Metridiochoerus) but also the root formation.
In Metridiochoerus, the roots are much shorter than the crowns. In Pronotochoerus
they are always longer and morphologically quite different.
Dale (1948) described a new pig from South Africa as Pronotochoerus shawi. From
the description and illustrations, it is not certain that this specimen should be attri-
buted to Pro7iotochoerus. If the roots of the third molar were exposed, this point
could be settled. Moreover, Dale’s specimen, in which all but the talonid of the third
molar is already in wear and the first molar extremely worn, carries a well-developed
fourth premolar, as well as a third premolar, with faint suggestions of the root sockets
of a second premolar. These characters do not suggest Pronotochoerus. Pronoto-
choerus, as known from East Africa, has a rudimentary fourth premolar, and a jaw
in such an advanced state of wear as Dale’s specimen would certainly not have a
third premolar present.
Genus NOTOCHOERUS Broom
(= Gerontochoerus Leakey)
Diagnosis. — Suidae with rooted, hypsodont molars. A clear line of demarcation
separates the crowns and roots in the molars, even in unerupted or partially erupted
teeth. Premolars lost early in life, so that dental formula in full adults is M3, Ma,
Ml, P4, Cl and P. In upper third molars, the second pair of pillars, and those posterior
to it, may be separated from each other by a gap, so that the enamel does not touch at
the median line. In lower third molars, the pairs of lateral pillars always meet along
EAST AFRICAN PLEISTOCENE SUIDAE
31
the median line, each pair being separated from the next by one or more median pillars.
Enamel of molars always covered with cement. The pillars of upper and lower molars
aligned in rows, even in the talon and talonid, and not in complex, irregular grouping,
such as is seen in Metridiochoenis.
Notochoeriis capensis Broom
1925 N otochoerus capensis Broom, p. 307, text-fig.
1949a Notochoerus capensis Broom : Cooke, p. 27, text-fig. 13.
Holotype. — Partial upper third molar. The holotype is in the Port Elizabeth
Museum.
That the holotype is the last molar of the upper dentition is shown by the arrange-
ment of the pairs of lateral pillars, cf. generic diagnosis above, also PI. lo.
Horizon. — The diamond gravels of the Vaal River.
This probably means the Middle Pleistocene gravels, which yield quantities of
Acheulian type hand-axes.
Locality. — Longlands, near Kimberley, Central Province, South Africa.
Diagnosis. — Broom did not give a diagnosis of the species; the following is
suggested: A N otochoerus of very large size, in which the enamel of the cusps forming
the pillars of the upper molars is folded in an irregular and complex pattern.
Viewed from the side, the individual pillars are widely separated from each other at
the top, leaving marked and deep lateral valleys between each pair.
Notes. — The holotype has been discussed and well figured by Cooke and these,
together with the original account by Broom, provide an adequate description of the
species which is referred to here because it is the genotype. The species is not repre-
sented in the East African material.
Arambourg (1947) attributed a group of specimens from the Omo Valley to
N otochoerus capensis, but examination of the original materia) in Paris, as well as of
material ascribed by me to Gerontochoerus (Leakey, 1943), shows that all this East
African material should be regarded as a species of Notochoerus distinct from Noto-
choerus capensis of South Africa.
Notochoerus euiliis (Hopwood)
(Plate 10)
1926a Hylochoerus euilus Hopwood, p. 21, pi. 2, figs. 7-10,
text-fig. 7a.
1942 Notochoerus serengetensis Dietrich, p. no, pi. 17,
fig. 129; pi. 18, figs. 137, 138, 140, 142-144.
1943 Gerontochoerus scotti Leakey, p. 47, pis. 15-17.
1947 Notochoerus capensis Broom; Arambourg, p. 354,
pi. 18, fig. 4; pi. 19, figs. 1-4.
Hopwood (1926a) described certain fragmentary pig teeth from the Kaiso Bone
Bed in Uganda which he assigned to the living genus Hylochoerus under the new
specific name H. euilus. Examination of this and other material leaves no doubt that
32
FOSSIL MAMMALS OF AFRICA No. 14
the Kaiso teeth belong to the genus Notochoerns, and that they differ from the South
African species N. capensis sufficiently to justify the retention of Hopwood’s specific
name.
Subsequently certain fossil teeth from Shungura, Omo, were described as
Gerontochoenis scotti gen. et sp. nov. (Leakey, 1943). Re-examination of these
specimens as well as of similar material collected by Arambourg in the Omo ^Mlley,
confirms that it should all be regarded as of the same genus and species as the Kaiso
fossil pigs here referred to Notochoerus euilus (Hopwood).
In 1942, Dietrich published an account of some specimens of fossil pigs from the
Serengeti, Tanganyika Territory, under the name of Notochoerus serengetensis. This
material also corresponds closely to that from the Omo Valley and from Kaiso and
should be referred to Notochoerus euilus.
Syntypes. — Four fragments of molar teeth (M. 12613, Brit. Mus. Palaeont. Dept.).
Horizon. — Lower Pleistocene, decline of the Kageran pluvial.
Locality. — Kaiso Bone Beds, Lake Albert.
Diagnosis. — Hopwood’s diagnosis of N . euilus was based on fragmentary material
and the following new diagnosis is, therefore, suggested: a species of Notochoerus of
approximately the same size as Notochoerus capensis, but differing from it in the
enamel pattern of the paired cusps in the upper and lower third molars. These, in
Notochoerus euilus, are predominantly dumb-bell in shape. The anterior part of the
third molars comes into wear long before the posterior end. The talon, in particular,
is frequently not erupted until advanced age.
The descriptions given by Leakey of Gerontochoenis and by Arambourg of the
specimens which he attributed to N otochoerus capensis provide an adequate account
of the characters of this species, but, in order to facilitate comparison, illustrations of
the original syntypes of Gerontochoerus are given in Plate 10, figs. 1-3.
The only new material, in the collection under review, which can be attributed to
this species is a series of broken teeth from Laetolil. Two of these are figured
(M. 15117a, h, Brit. Mus. Palaeont. Dept.). They compare very closely indeed with
specimens from the same site which Dietrich (1942) called N otochoerus serengetensis.
(See Plate 10).
Notochoerus comp act us sp. nov.
(Plate II, figs. I, 3; PI. 12)
Diagnosis. — A species of Notochoerus, with hypsodont, very strongly rooted,
third molars, narrow in relation to their length. The pairs of pillars are compressed
more closely than in N otochoerus capensis or Notochoerus euilus, giving a very compact
appearance. The valleys between the pairs of pillars are very reduced. Third molars
are covered with cement. In fully adult specimens, the premolars are reduced to the
fourth only, which is vestigial. The body of the mandible is inflated on the buccal
side and very thick, a character in which N otochoerus compactus differs markedly
from Pronotochoerus and Mesochoerus. The lower canines have slightly convex buccal
and lingual faces, as in Pronotochoerus.
Syntypes. — A. A mandible in which the right ascending ramus is missing and
which has suffered other minor damage, but is reasonably well preserved (M. 17084,
Brit. Mus. Palaeont. Dept.).
EAST AFRICAN PLEISTOCENE SUIDAE
33
B. A fragment of mandible with second and third molars (M. 17085, Brit. Mus.
Palaeont. Dept.).
Horizon. — Middle Pleistocene, Kamasian pluvial.
Localities. — Bed II: sites B.K. and S.H.K. at Olduvai.
Description. — First Syntype. (PI. ii, figs, i, 3). This specimen consists of the
greater part of a well preserved mandible from B.K. II. The right ascending ramus
is missing, having been broken off about 45 mm. behind the third molar. On the left
side, the ascending ramus, including the condyle, is well preserved, but the coronoid
process is missing. The body of the mandible on both sides is well preserved, except
in the region of the incisors. On both sides, the second and third molars are preserved,
as well as the sockets of the first molars and of the vestigial fourth premolar. On the
left side, the broken root of the canine is preserved in its socket, but on the right it is
missing. Owing to the damage anteriorly, it is impossible to say how many incisor
teeth were present in adult life.
SECOND molars: These are exceedingly worn and the enamel pattern is reduced to a
circle of enamel following the contour of the crown of the tooth surrounding a m.ass
of dentine, from which a few, small, rudimentary pillars appear as islands. The
length of both the second molars is 18-5 mm. and the breadth 15 mm.
THIRD molars: Both these are fully erupted and the talonids are in full wear. Owing
to advanced age, the enamel of each median pillar has linked up with that of the
lateral pillars posterior to it: it thus forms a more complex pattern than is seen in
less worn teeth of the species, where the characteristic Notochoerus pattern is main-
tained. The deep valleys, which separate the pairs of pillars, when viewed laterally,
in both Notochoerus capensis and Notochoerus euilus, are, in this species, reduced to
the merest indentations between the pairs of pillars. In this respect, Notochoerus
comp actus corresponds much more closely with the genus Tapinochoerus. The two
third molars have identical measurements; length 59-5 mm., width 24 mm.
FOURTH premolar: It is clear from the socket of the fourth premolar that this tooth
was very small.
canine: Examination of the broken stump of the canine on the left side shows that
it was slightly convex on both the lingual and buccal faces, without any sign of the
lateral grooves that occur in Potamochoerus. The enamel, which covers the buccal
and lingual sides of the tusk, exhibits a curious lattice-work pattern. This appears to
be characteristic of the species and has not been seen in any other East African fossil
pig. The angle of the canines to the body of the mandible is more obtuse than in
modern East African pigs.
The symphysis is relatively short in comparison with, for example, that of
Pronotochoerus or Mesochoerus. The relative size is seen in Plate ii, where this jaw
is placed next to that of a modern Phacochoerus.
Second Syntype. — (PI. 12, figs. 2, 3). In this specimen, which is a mandibular
fragment containing M3 and Mg, the bone has been cut away from the region of the
roots of the third molar in order to expose them for study. The third molar is slightly
smaller than in the first syntype, but the whole surface of the crown is in wear,
although the hind part of the talonid has only just reached this stage. The roots are
long and well developed, those on the talonid being partially fused together, as in
34 FOSSIL MAMMALS OF AFRICA No. 14
Pronotochoerus, but to a lesser degree. There is a clearly marked dividing line between
the cement-covered crown and the roots. The following table sets out the measure-
ments (in millimetres) of this tooth, including the height of the crown at various
positions corresponding to the length of the roots at the same position:
Length
Width
Height of
crown at
first
pillars
Height of
crown at
second
pillars
Height of
crown at
end of
talon
Length of
root at
first
pillars
Length of
root at
second
pillars
Length of
root at
end of
talon
55-5
M'5
15-5
23
38
45
48
29
The enamel pattern of the crown of the third molar of this specimen is, like that
of the first syntype, very compact, with the vaUeys which separate the pairs of pillars
greatly reduced. Each pair of pillars, the components of which meet at the median
line, is separated from the next pair by a median piUar. The second molar is slightly
damaged and also in a fairly advanced state of wear. As preserved, it has a length
of 24 mm. and a width of 14 mm.
Additional Material. — In addition to the above two specimens, there is a
fragment of a mandible, marked Old. B.K.II, 53/159 (PI. 12, fig. i). This specimen
contains the second and third molars intact, together with the sockets for the first
molar and for a vestigial fourth premolar. The specimen corresponds closely with the
second syntype and has the following measurements for the third molar: length
56-5 mm. and width 15 mm.; and for the second molar: length 25-5 mm. and width
14 mm. Several broken lower canines exhibiting the characteristic lattice pattern on
the enamel are in the collection.
Notochoerus hopwoodi sp. nov.
(Plate 13)
1934 N otochoerus dietfichi Hopwood, p. 548 (paratype only)
As will appear when the genus Tapinochoerus is discussed, the holotype of
Hopwood’s Notochoerus, dietrichi, published in 1934, is not, in fact, a Notochoerus at
all, but a specimen of T apinochoerus meadowsi. The name N otochoerus dietrichi has,
therefore, to be relegated to the synonymy. Hopwood’s paratype, however, consisted
of a fragment of a mandible from Bed III, Olduvai, and, when the bone was dissected
from the roots of the tooth, it became apparent that this paratype does represent a
true N otochoerus that differs in several essential characters from any of the other
known species of Notochoerus.
Diagnosis. — A species of N otochoerus with lower molars which may be as long as
those of N otochoerus capensis, but are much more hypsodont, as well as much narrower
in proportion to their length; the roots of the lower third molars are proportionately
much shorter than those of other species. The pillars of the third molars are set more
closely together than in Notochoerus capensis and N. euilus, but less so than in
N otochoerus compactus. Notochoerus hopwoodi seems, in some respects, to be inter-
EAST AFRICAN PLEISTOCENE SUIDAE
35
mediate, in its morphology, between the two former and the latter species. The
mandible lacks the lateral inflation of N. comp actus.
Holotype. — Part of a lower left mandibular ramus containing Mg fully erupted,
M3 incompletely erupted and the root-sockets of and P^ (M. 14685, Brit. Mus.
Palaeont. Dept.).
Horizon. — Middle Pleistocene, interpluvial between Kamasian and Kanjeran.
Locality. — Bed III, Olduvai.
Description. — This specimen consists of a mandibular fragment, which is broken
off posteriorly about 42 mm. behind the talonid of the third molar and anteriorly just
behind the canine tooth. The sockets of the fourth premolar and the first molar
indicate that they were about to be shed; the small size of the former shows that it
was a vestigial tooth. Mj is well preserved and has long roots, which, in the state of
wear of the specimen, are considerably longer than the height of the crown. The
measurements of the second molar are: length 32 mm., width 17-5 mm. The third
molar is not fully erupted, although the anterior part of the tooth is already partially
worn and fully developed.
In describing this tooth Hop wood (1934) measured it as exposed in wear during
life. The bone has now been removed from the roots and from the posterior area
of the crown and it is seen that the total length is, in fact, 85 mm. There are two
strongly marked roots which are, however, much shorter than the respective heights
of the anterior and second pair of pillars. Roots were also in process of formation on
the posterior half of the tooth. The width of the third molar is 17 mm. The corpus
of the mandible completely lacks the lateral swelling, which is so marked a feature of
N otochoerus compactus and, in this respect, it more closely resembles Pronotochoerus
than N otochoerus.
A broken upper third molar (M.17115, Brit. Mus. Palaeont. Dept.), which was
found in the top levels of Olduvai Bed IV at site N.S.C., is provisionally attributed to
N otochoerus hopwoodi. It is clearly different from comparable specimens of Noto-
choerus euilus and also from N otochoerus compactus (see PI. 13, figs. 3, 4).
Discussion. — One of the major differences between the third lower molar of
N otochoerus hopwoodi and the corresponding tooth of N otochoerus euilus lies in the
narrowness in relation to the length. In N otochoerus hopwoodi, as represented by the
holotype, the index ^ jg 20, compared with an average of 26-8 in
N otochoerus euilus. Another major difference between the two species lies in the
enamel pattern, which in N otochoerus hopwoodi is much less complex and the interior
arms of the 'dumb-bell’ pattern are much reduced compared with the exterior ones.
On the other hand, the pattern of the crown of the lower and second third molars
superficially resembles that to be seen in Tapinochoerus, so that it would be easy to
confuse the two genera if the crown pattern were taken as the only criterion.
As this species is represented by only two specimens in the large Olduvai collec-
tions, it would appear to be relatively rare and probably one which was evolved
under very dry conditions, having a totally different ecology from most of the other
Olduvai pigs. This view is supported by the fact that the only other specimen which
can be attributed to N otochoerus hopwoodi is a skull from the Rawi fish beds, which
belong to the same interpluvial.
FOSSIL MAMMALS OF AFRICA No. 14
Notochoerus cf. hopwoodi
(Plate 14)
3^>
This pig skull (M. 15940, Brit. Mus. Palaeont. Dept.) from the upper part of the
Rawi fossil beds near Homa Mountain, is of an immature individual and it cannot be
specifically identihed with any degree of certainty. The general characters of the-
dentition, however, leave no room for doubt that it belongs to the genus Notochoerus.
The deposits in which it was found were formed during the closing stages of the
Kamasian pluvial, when desiccation was increasing, and they are contemporary with
the lower part of Bed III at Olduvai. The latter is the deposit from which
Notochoerus hopwoodi was obtained and since, in so far as the size of the teeth is
concerned, the resemblances are more with that species than with either N . compactus
or N. euilus, the skull may provisionally be regarded as belonging to N . hopwoodi.
Although specific identification is uncertain, this specimen is of considerable
importance, because it reveals, for the first time, the fundamental cranial characters
of the genus, thus making it possible to assess more correctly both the relationship of
Notochoerus to the living genera of pigs in Africa and its affinities with other fossil
forms.
The skull as a whole is remarkably well preserved (see PI. 14, fig. 3), but the malar
bones on both sides are missing, as well as the jugal projection of the temporal bones.
The lachrymal on the left side is lost, and that on the right is incomplete. The
anterior parts of both nasal bones, the premaxillae, the tips of the buUae and both
the styloid processes have been broken off. The crowns of the canine teeth on either
side are missing, leaving tho roots and the sockets. The inferior region of the left
maxilla is damaged.
The skull has suffered slight crushing and distortion during fossilisation, but this
is insufficient to prevent accurate assessment of its major characters.
Morphology of the Skull. — In its general morphology, this skull exhibits a
strange mixture of characters recalling each of the three living genera of African
Suidae — a fact which can be appreciated from an examination of Plate 14, where the
skull is shown side by side with typical examples of Phacochoerus, Potamochoerus and
Hylochoerus. For convenience, the characters linking this fossil skull with each of the
three living genera will be taken in turn, beginning with the resemblances to
Hylochoerus.
RESEMBLANCES TO HYLOCHOERUS.--Wh.&n viewed from above, the posterior region
of the skull, from the orbits to the occipital, is seen to have the general shape of
Hylochoerus] in particular, the line of the temporal crest from the externa] orbital
processes to the lateral edges of the occipital crest has a similar formation and relative
length to Hylochoerus and is totally unlike the morphology of this region of the skuU
in Phacochoerus or Potamochoerus. It should be noted, however, that, when viewed
from above, the line of the occipital crest in Notochoerus is almost straight and lacks
the convexity in the median line noticeable in the three living genera, though to a less
extent in Hylochoerus.
EAST AFRICAN PLEISTOCENE SUIDAE
37
There is a slight depression between the orbits, on the roof of the skull. This is
similar to that found in some, but not all, individual specimens of Hylochoerus and
is quite unlike the type of concavity seen in PhacocJioeriis. In Potamochoerus, there
is either a flatness or even a convexity in this region. The form of the external
orbital process is also similar to that in Hylochoerus and dissimilar to that in the
other two genera.
Although the lachrymal is missing on the left side and somewhat damaged on the
right, there is ample evidence to show that it more closely resembled that of
Hylochoerus than that of Potamochoerus and was totally unlike the narrow elongated
lachrymals of Phacochoerus. Associated with the relatively short and broad lachry-
mals of Hylochoerus type, is the long suture contact between the frontal bones and
the maxillae. A somewhat similar, but rather more limited, frontal-maxillary contact
can be found in Potamochoerus, but it is with Hylochoerus that the greatest resem-
blance is seen. In Phacochoerus, a visible contact between the frontals and the
maxillae is very rare; where it occurs it is usually of ver}^ limited extent. The more
normal relationship in Phacochoerus is one between the forward projection of the
elongate lachrymals and the nasal bones, resulting in a complete separation of the
frontals from the maxillae. The relative width of the occipital bone to the width
across the skull — seen from the near margin of one orbit to the other — is very similar
to that seen in Hylochoerus and quite unlike that of Phacochoerus.
When viewed from the palatal aspect, there are also certain skull characters in
the fossil which resemble Hylochoerus. These are:
(a) A flattened tuberosity on the palatine process;
(b) The general palatal shape in the region anterior to the premolars;
(c) The position of the palatal foramina;
(d) The long bony buttress containing the roots of the canine teeth, which extends
backwards to within lo mm. of the maxillary foramina;
(e) The orientation of the canine teeth (and, in particular, of the roots of these
teeth) is very similar to the form seen in juvenile Hylochoerus and, to some
extent, in adults.
Although the premaxillae are missing, it would appear from their sutures that
they were short and rather similar to the Hylochoerus form.
RESEMBLANCES TO POTAMOCHOERUS. — In Certain characters, the resemblances of the
fossil skull are not to Hylochoerus but to Potamochoerus. The coronal suture, separ-
ating the frontals from the parietals, starts behind the external orbital angles and
curves backwards towards the occipital crest, in a manner much more marked than
in Hylochoerus or Phacochoerus and reminiscent of, but more exaggerated than, the
Potamochoerus form. It should, however, be mentioned that in very young Phaco-
choerus skulls a similar condition is sometimes seen, but is lost with advancing age.
The paired foramina on the frontal bones, as well as the flattening of the anterior
region of the frontals, as they approach the contact with the nasals, very strongly
recall the Potamochoerus pattern and are quite unlike the condition seen in the other
38 FOSSIL MAMMALS OF AFRICA No. 14
two living genera. Moreover, the junction of the nasal bones with the f rentals is in
the form of an inverted ‘V’, as in Potamochoerus only.
Although the nasal bones are broken anteriorly, the part that is preserved com-
pares very closely with the Potamochoerus pattern, being exceedingly flattened.
RESEMBLANCES TO PHACOCHOERUS. — Although, in the past, Notochoerus has been
frequently regarded as standing closer to Phacochoerus than to either Hylochoerus or
Potamochoerus because of its dental resemblances, it is most noticeable that when the
skull morphology is examined the similarities to Phacochoerus are fewer than to
the other two genera. Among characters in which the fossil skull resembles
Phacochoerus and is quite unlike the other two genera are the following;
(a) The form of the occipital condyles;
(b) The shape of that part of the bullae which is preserved;
(c) The angle of the basi-occipital;
(d) The elongate, shallow pterygoid fossa.
The position of the maxillary foramina is not really of the type seen in any of the
living pigs, but again is a little closer to Phacochoerus than to the other two.
Description of Teeth. — The root sockets of the second and third premolars are
just visible on the alveolar surface, but they were already partly closed at the time
of death, showing that these teeth had been shed before the third molar was erupted.
The fourth premolar is very small, of vestigial character, and was not fully erupted.
The first molar is well worn, but the second molar has only recently come into wear
and the posterior part is still 'unabraded. The third molar was not fully erupted,
although the anterior pillars had just emerged from the alveolar margin. The first
and second molars are of typical Notochoerus form. The first molar is composed of
two pairs of lateral pillars of dumb-bell shape, each pair meeting in a median line and
separated from each other by a single median pillar. The tooth has well-developed
roots. The second molar is also composed of two pairs of lateral pillars, the elements
of each pair meeting on the median line, while the pairs are separated from each other
by a single median pillar. Anteriorly, there are two subsidiary pillars, one median
and one lingual, while there is posteriorly a talonid of a series of small cuspules. The
unworn and only partially erupted third molar does not show its enamel pattern, but
it is in other respects typical of Notochoerus and has a very clearly defined dividing
line separating the hypsodont crown from the roots. These third molars do not
resemble Tapinochoerus teeth.
The canine teeth are broken away at the alveolar margin, but their stumps are
visible; these are covered with enamel on all faces and carry marked longitudinal
ribbing, much as that seen in Hylochoerus adults and completely unlike Phacochoerus.
These broken roots so strongly resemble the teeth provisionally ascribed by
Arambourg to Mesochoerus (— Omochoerus) heseloni, that it seems likely that they
should have been referred to Notochoerus etdhis, not to Mesochoerus.
The following are the principal measurements of the skull and teeth, compared
with examples of the three living genera;
EAST AFRICAN PLEISTOCENE SUIDAE
39
N otochoerus
cf. hopwoodi
Phacochoerus
Hylochoerus
Potamochoerus
Length of skull from occipital
crest to anterior end of left
(mm.)
(mm.)
(mm.)
(mm.)
ma.xiUa on palate
Maximum width of occipital on
404
347
327
294
the crest ....
Minimum width of post-orbital
125
80
97
76
constriction on temporal crests
Maximum width from one exter-
82
37
71
21
nal orbital process to another
Minimum width between upper
151
129
107
89-5
margins of the orbital rims .
Maximum width across nasal
107
109-5
81
68
bones ....
Minimum width of post-canine
53-5
44-5
42
43
constriction
Maximum width at external
79
55
58
47
alveolar rim of canines .
145
133
95
93
DISCUSSION OF THE GENUS NOTOCHOERUS
The genus Notochoerus was erected by Broom (1925) on the basis of an incomplete
gigantic tooth, which he described as part of a lower third molar of N otochoerus
meadowsi gen. et. sp. nov. Subsequently in 1931, Broom described what he believed
to be another species of N otochoerus under the name of N. paiceae, but this was later
shown by Shaw & Cooke (1941) to be distinct from N otochoerus and placed in their
new genus, Mesochoerus. At the same time, these two authors described another
species of Notochoerus under the name of Notochoerus hroomi: this has since been
shown to be a member of the Tapinochoerus group; it is now regarded as identical
with Tapinochoerus modestus Van Hoepen, 1932.
Shortly after Broom’s original account of N otochoerus capensis had appeared,
Hopwood (1926), in dealing with some fossil remains from the Kaiso Bone Bed in
Uganda, described certain fragmentary pig teeth under the name of Hylochoerus
euilus, while later (1943), in discussing fossil pigs from Shungura, Omo, Southern
Abyssinia, I described the new genus and species Gerontochoerus scotti. Both
Hopwood’s specimens and mine are here ascribed to Broom’s genus Notochoerus.
As a result of the revision that has now been carried out and of the descriptions
in the present paper, a clearer picture of the characteristics of N otochoerus appears.
It is a genus of Suidae with large, hypsodont third molars, which have a clearly
defined line of demarcation between the crown and the well developed roots. These
roots are developed on the talon and talonid of the third molars before those teeth
40 FOSSIL MAMMALS OF AFRICA No. 14
have been fully erupted. It is this well defined line of demarcation between the crown
and the roots, together with tlie strong development of the roots, that clearly
distinguishes the third molars of Notochoerus from those of the genus Tapinochoerus
— but there are noticeable differences in other respects, including skull characters (see
below) .
In South Africa, both N. paiceae and N. broomi have been taken out of the genus
Notochoerus and transferred, respectively, to Mesochoerus and Tapinochoerus, whereas
in East Africa the material described as Hylochoerus euilus is quite clearly typical of
Notochoerus, as is the material from the Omo described as Gerontochoerus. Arambourg
recognised that Gerontochoerus was synonymous with Notochoerus, but he did not
appreciate the difference between the early Pleistocene Notochoerus of the Omo
Valley and of Kaiso and the species N. capensis in South Africa, which is probably of
Middle Pleistocene age. In Tanganyika, the specimens collected by Dr. Kohl-Larsen
and described by Dietrich (1942) under the name Notochoerus serengetensis are clearly
identical with the Omo and Kaiso material.
Hopwood’s trivial name for the Kaiso specimens has the priority, so far as the
larger East African members of the Notochoerus genus are concerned, and it is retained
for the Lower Pleistocene members of this genus. It should be noted that the
Notochoerus material from Kaiso was found in deposits formed under conditions of
climatic change, when the weather was getting drier, which is probably also
true of the Laetolil deposits in which Dietrich’s material was found. In the Omo
Valley there are somie deposits which belong to a much drier phase and unfortun-
ately it is uncertain, at the present time, whether the Notochoerus material from that
area came from the pluvial deposits or from the deposits formed during the period of
increasing desiccation. On the whole, it seems likely that the early Notochoerus euilus
was a pig associated with somewhat dry conditions.
In the Olduvai beds a true Notochoerus also appears in the deposits formed under
dry conditions in Bed III and at the base of Bed IV, while at Rawi there is also a
N otochoerus in deposits formed during increasing desiccation. On the other hand,
during the wet conditions under which Beds I, II and IV were formed at Olduvai,
as well as at Olorgesailie, Tapinochoerus is common, although one specialised species
of N otochoerus {N . compactus) occurs as a rare fossil.
The relationship of N otochoerus and Pronotochoerus is one that cannot be fully
determined until fossiliferous Pliocene deposits are found in East Africa. Both genera
occur in the Lower Pleistocene, but there are indications that Pronotochoerus may
represent a survival of an earlier Pliocene form into deposits yielding Notochoerus,
which may be a derivative branch of the same stock.
In general terms, it may be stated that in respect of its dentition the genus
N otochoerus (as well as Metridiochoems, Pronotochoerus and Tapinochoerus: see below)
stands closer to Phacochoerus than it does to the group which includes Sus,
Potamochoerus and Mesochoerus and Dietrich has suggested a division into two sub-
families, the vSuinae and the Phacochoerinae. These sub-families do not appear to be
justified at present. If it were done, it would mean that the group placed in the sub-
family Suinae would include species with many characters reminiscent of the suggested
sub-family Phacochoerinae, and vice versa. It therefore seems better simply to retain
the family Suidae and not to attempt to divide it into sub-families at present.
EAST AFRICAN PLEISTOCENE SUIDAE
41
Genus TAPINOCHOERUS Van Hoepen & Van Hoepen
(= Notochoerus of the same authors, in part)
Diagnosis. — Suidae with strongly hypsodont third molars, in which there is no
clear line of demarcation between the crowns and the roots. In some species roots
are, to all intents and purposes, never developed, the pulp cavity remaining open to
extreme old age. In other species, small roots form, especially on the first and second
pairs of pillars of the third molars, at an early age, but these differ completely in
character from those of the genus Notochoerus. Lower molar teeth are composed of
pairs of piUars, each pair separated from the other by median pillars. In the hrst
two pairs of pillars, the elements meet, or nearly meet, along the median line, whereas
components of the other pairs of pillars are usually separated. In the upper molars,
the cusps of the anterior pair of pillars meet in the median line, but the subsequent
pairs of pillars (including usually the second pair) are separated by a row of median
pillars, which are not necessarily contiguous.
Notes. — The new genus and species Tapinochoerus modestus was erected by the
Van Hoepens on the basis of some molars found at Cornelia, in South Africa, which
they recognised as having essential differences from Broom's Notochoerus. Subse-
quently (1941) Shaw & Cooke realised that the fossil described by Broom (1928) as
Notochoerus meadowsi also differed essentially from Notochoerus and transferred this
species to the genus Tapinochoerus. In 1949, Cooke drew attention to the fact that
the specimen from Olduvai, attributed (Leakey, 1942) to Notochoerus dietrichi
Hopwood was, in fact, identical in all respects with T apinochoerus meadowsi. This
is certainly correct (see above).
Tapinochoerus meadowsi (Broom)
(Plates 15 — 17; Plate 18, figs. 1-4)
1928 N otochoerus meadowsi Broom, pi. 439, text-fig. i.
1931 Phacochoerus meadowsi (Broom) Dreyer & Lyle, pp. 9, ii.
1932 Kolpochoerus sinuosus v. Hoepen & v. Hoepen, p. 59, text-figs. 72-77.
1934 N otochoerus dietrichi Hopwood, p. 548 (holotype only).
1938 N otochoerus capensis Broom : Shaw, p. 34, text-fig. 5.
1939 N otochoerus capensis Broom : Shaw, p. 88, text-hg. 9.
1942 N otochoerus dietrichi Hopwood : Leakey, p. 185, pi. 62 (right), text-fig. la.
1942 N otochoerus dietrichi Hopwood : Kent, pp. 124, 126.
1947 Notochoerus dietrichi Hopwood : Vaufrey, p. 367.
1947 Phacochoerus africanus fossilis v. Hoepen & v. Hoepen : Arambourg,
p. 359, pi. 20, hgs. 5, 5«.
1948 Notochoerus dietrichi Hopwood : Vaufrey, pp. 147-8, text-hg. 4.
1949 Tapinochoerus meadowsi (Broom) Cooke, p. 28, text-figs. 14, 15.
Diagnosis. — A Tapinochoerus of large size, in which the premolar series has been
reduced to a vestigial fourth premolar by the time the third molars have erupted.
42 FOSSIL MAMMALS OF AFRICA No. 14
The latter tooth is also usually shed, together with the first molar, long before old age.
Incisors reduced in number to four in adult life.
Holotype. — A third lower molar, originally described by Broom in 1928 as
Notochoerus meadowsi, belongs to the McGregor Memorial Museum, Kimberle}^
Horizon. — Middle Pleistocene. (The diamondiferous gravels of the Vaal River at
Kimberley yield quantities of Chelles-Acheul hand-axes and are usually regarded as
of Middle Pleistocene age).
Locality. — The diamond gravels of the Vaal River in the Kimberley district.
Notes. — Broom’s original account of this tooth (1928) has been supplemented by
an excellent description, with figures, by Cooke in 1949; this should be consulted.
The following maximum measurements of the holotype are repeated for reference:
length 76 mm.; width 19 mm.; height 64 mm.
As already mentioned (p. 34), the type of Notochoerus dietrichi Hopwood from
Olduvai, published in 1934, is an upper third molar and not a Notochoerus, but has aU
the characteristics of Tapinochoerus meadowsi.
Additional Material. — Since 1934 the Olduvai Gorge deposits have yielded a
very considerable amount of additional material attributable to Tapinochoerus and
further specimens have also been obtained from Olorgesailie and Kanjera, in Kenya.
While all this new material cannot be discussed in detail, special reference must be
made to the following specimens, all of which resemble Tapinochoerus meadowsi so
closely that they are referred to that species:
A. The greater part of a very large jaw, together with an associated fragmentary
skull from Olorgesailie.
B. Eight upper third molars.
C. Thirteen lower third molars.
All of these specimens come from deposits of Middle Pleistocene age; some belong
to the Coryndon Museum, Nairobi, and some to the British Museum. The registered
numbers of the more important are quoted below (p. 45).
A. THE associated MANDIBLE AND FRAGMENT OF SKULL FROM OLORGESAILIE. —
These are the remains of a young adult, with the third molars just coming into full
wear. On the left side, the mandible is almost complete, except for the inferior
margin of the body, but on the right it is broken off behind M3 and the body is
damaged inferiorly, although the teeth are weU preserved. The mandible is very
large, the length from the anterior border of the alveolus, between the sockets of
the incisors, to a line perpendicular to the most backwardly projecting part of the
condyle being 488 mm., while the distance from the mid-point of the alveolus to the
most backward point of the third molar is 316-5 mm. The huge size, in relation to
jaws of modern wart-hogs and giant forest hogs, will be seen in the illustration
(PI. 15, figs. I, 2).
The body of the mandible is relatively massive, but, in spite of its much greater
size, it is not thicker or heavier than mandibles of the much smaller Pronoto-
choerus. The width between the inner margins of the alveolus, in the region of the
canines at their anterior point, is 140 mm., whereas the over-aU width, across the
EAST AFRICAN PLEISTOCENE SUIDAE
43
anterior part of the mandible on the lingual side of the canines, is 176 mm. The
narrowest width of the jaw behind the canines is 120 mm. The length of the sym-
physis, 139 mm., is relatively short compared with 102 mm. in Mesochoerus
olduvaiensis, which is a much smaller pig in other respects, and 119 mm. in Pronoto-
choenis nyanzae, also a much smaller creature.
The incisor teeth have been lost after death, but the sockets indicate that only
four small incisors were present and these were probably in process of being shed.
The canines are long, but not very massive, and project 129 mm. from the alveolar
margin, measured on the chord from alveolus to tip. These teeth have slightly convex
surfaces on both the alveolar and lingual aspects, with no trace whatsoever of a
groove; they carry enamel on both these faces. These tusks are only worn at the
extreme tips. There is no trace of a root-socket for P^, P^ or P3, while P^ is represented
by a very small root-socket which can only have held a completely vestigial tooth
about to be shed. Similarly, had undoubtedly been shed even before P^ was finally
thrown off, since the alveolar margins round the root-sockets of are practically
fused over. These facts suggest that in a fully adult Tapinochoerus the cheek teeth
would be reduced to Mg and M3 only.
The second and third molars are preserved on both sides of the jaw. The second
molars are relatively large and considerably worn; they are strongly rooted. The
enamel pattern is complex, as a result of the increasing wear; the enamel of the
anterior and posterior pillars has run together to form a continuous pattern.
These second molars have strongly projecting heels, which come from above the
root level, so that, with advancing wear, the size of heel would be progressively
reduced. The measurements of both second molars are: length 34 mm., width of
anterior pillars 18 mm. and width of posterior pillars 19 mm.
The third molars have developed to a point where even the posterior ends of the
talonids are just coming into wear, while the anterior cusps are a little more worn.
The enamel of the two elements composing the second pair of pillars does not quite
touch in the median line and, posteriorly, the remaining lateral pillars are separated
from each other by a row of rather elongated median pillars. The valleys between
the pairs of pillars are fairly strongly marked on the buccal and lingual sides. The
maximum length of the left third molar could only be measured by removing the tooth
from the jaw: it is 80 mm. The right third molar has not been so removed, but it is
of approximately the same length. The root area has been cleared of its bony wall
on the left side to reveal a complete lack of a line of demarcation between the crowns
and the root area. The pulp cavities are open. The height, as preserved, at the
fourth pair of pillars is 60 mm. The maximum width of the tooth on the anterior pair
of pillars is 20 mm.
Associated with the mandible just described, was part of a huge skull, containing
the second and third molars on both sides and the sockets of the canine teeth (PI. 15,
fig. 3). The premaxillary region is completely broken away, together with part of the
palate and part of the nasal bones; posteriorly, the whole of the skull is missing behind
the third molars and the junction of the nasal bone with the frontals.
Although the upper canine teeth are missing, it is clear from the nature of the
sockets that they were of very large size and that they were set at an angle facing
44 FOSSIL MAMMALS OF AFRICA No. 14
far more forward than in any of the living genera. There are only very shallow
depressions between the upper part of the alveolar wall of the canine teeth and the
region of the maxillary-premaxillary suture and the roots of the canines must have
extended backwards to a point almost over the fourth premolar. The maxillary
foramina are unusually large and there is strong doming of the bones of the maxillae
and of the nasal bones quite unlike the condition seen in any modern African genera
of wild pig. Although only fragmentary, a sufficiently large piece of the skull is
preserved to indicate that, when complete, it was probably larger than that of a
modern black rhinoceros.
On the palatal surface, the root-sockets of M^ are preserved and, though these
teeth were lost after death, they were clearly about to be shed. They were apparently
three-rooted. The second molars are in full wear and measure 32 mm. long by
20 mm. wide. Each tooth was composed of two pairs of pillars with a well marked
talonid, but, as a result of wear, the enamel pattern is now somewhat confused.
The upper third molars are not fully erupted and are made up of pairs of pillars, the
hrst pair being separated from the second by a single median pillar and with the two
elements of the hrst pair touching medianly. The elements composing the second
and succeeding pairs of pillars are separated from each other by a row of median
pillars, which extend right down the middle line of the tooth. The left third molar
has a maximum length of 82 mm., a maximum height on the fourth pair of pillars of
83 mm. and a maximum width of 23 mm. The dimensions of the right third molar
are comparable. The third molar teeth have no roots and the pulp cavities at their
bases are open.
Although this fragment of skull of Tapinochoerus meadowsi is incomplete, it is of
special importance because of the differences it exhibits when compared with the skull
of Notochoerus. This conhrms the different generic character of these two groups, in
spite of the similarity of the crown pattern of the teeth. Morphologically, in those
parts of the skull which are preserved, the resemblances are much more to Hylochoerus
than to Phacochoerus, with which Tapinochoerus has been so frequently associated
in earlier literature.
B. ISOLATED UPPER THIRD MOLARS. — In addition to the upper third molar described
by Hopwood (1934), there are now available for study eight well preserved upper
third molars in various stages of wear, as well as numerous broken specimens. The
most complete specimen was found at site C.M.K., Olduvai, in Bed IV (M.17109,
Brit. Mus. Palaeont. Dept.). It is slightly larger than the tooth described by
Hopwood, but in other respects resembles it very closely, as it does also the upper
molars in the skull from Olorgesailie described above (see PI. 17, figs. 5, 6).
The last pillar of the talon has just come into wear. The anterior pair of pillars
carries small roots and there are also traces of roots on the second pair of pillars, but
the rest of the tooth carries open pulp cavities. As in all specimens of Tapinochoerus,
there is no clear line of demarcation between the crown and the root area. The tooth
has a maximum length of 80 mm. and a length at the occlusal surface of 68 mm. The
width at the first pair of pillars is 28-5 mm. The enamel is covered with cement.
The maximum height at the posterior end of the tooth is 80-5 mm.
EAST AFRICAN PLEISTOCENE SUIDAE
45
Another specimen is an upper third molar from site B.K.II at Olduvai (Regd.
M. 17108, Brit. Mus. Palaeont. Dept.) (see PI. 17, figs, i, 2). The posterior part of the
tooth was not fully erupted at the time of death and only the anterior part is in
wear. The posterior end of the tooth is slightly damaged, as is part of the pulp
cavity area. The maximum length of the tooth, as preserved, is 67 mm., but the
actual length was greater. The maximum width at the anterior pair of pillars is
21 mm. and the maximum height, as preserved, is 85 mm.
Another slightly damaged upper third molar, also from site B.K.II, Olduvai,
has, as preserved, a maximum length of 71 mm., a maximum height of 96 mm. and a
maximum breadth of 20 mm.
An upper third molar from S.H.K.II, Olduvai (Regd. M.17107, Brit. Mus. Palaeont.
Dept.) has a maximum length of 70 mm., a maximum height of 95-5 mm. and a
maximum width of 21-5 mm. Only the anterior part of this tooth was fully erupted
and in wear (see PI. 17, figs. 7, 8).
A further specimen from site B.K.II at Olduvai has a maximum length of 70 mm.
and a maximum height of 89 mm., while the maximum width cannot be determfined
accurately owing to damage. There is also a number of other upper molars attributed
to Tapinochoerus meadowsi.
c. ISOLATED LOWER THIRD MOLARS. — Of the thirteen available isolated lower third
molars, there is first of all the specimen which was described and figured as
Notochoerus dietrichi (Leakey, 1942). This specimen is No. F.3027 of the Coryndon
Museum series (see PI. 18, figs, i, 2). It has a maximum length of 76 mm., a maximum
height of 75 mm. and a maximum width of 18 mm. It resembles very closely indeed
the type specimen of Tapinochoerus meadowsi from South Africa. The other twelve
lower third molars are typical in every respect and the following measurements may
be given of the more complete teeth. One is figured in PI. 18, figs. 3, 4 (M.17111, Brit.
Mus. Palaeont. Dept.).
Maximum Length
(mm.)
Maximum Height
(mm.)
Maximum Breadth
(mm.)
B.K.II, 53/378 .
71
77
16
F.3027, Old. Is..
76
75
18
M.17111, Old. Is.
69
66
.15
B.K.II, 1952/20 .
61
70
16
F.L.K.S. II, 1935
79 f 6?
74
21
B.K. II, 1935 .
75
76-5
19-5
There are a number of upper canine teeth which may possibly belong to the genus
Tapinochoerus, but the evidence is uncertain, and they are not described at present.
46
FOSSIL MAMMALS OF AFRICA No. 14
T apinochoerus 7ninutus sp. nov.
(Plate 18, figs. 5-8)
Diagnosis. — A dwarf species of Tapinochoerus, somehw^at smaller than T apino-
choerus modestus Van Hoepen & Van Hoepen, 1932. The upper molars have only
two pairs of pillars and a short talonid.
Holotype. — An upper third molar from the uppermost levels of Bed IVh Olduvai.
Regd. M. 17116a, Brit. Mus. Palaeont. Dept, (see PI. 18, figs. 5, 6).
Horizon. — End of the Middle Pleistocene; closing stages of the Kanjeran pluvial.
Description. — The holotype is an upper third molar of small size and the crown
of the tooth, which is not yet in full wear, has an occlusal surface of only 38 mm. and
a maximum length of 48 mm. The enamel pattern exhibits only two pairs of pillars,
behind which is a short talon composed of a few circular pillars. The two pillars of
the second pair are separated in the median line by one of a series of median pillars.
The first and second pairs of pillars carry short roots, whereas the rest of the tooth is
unrooted and has an open pulp cavity. The maximum height is 46 mm. and the
maximum width 15 mm. As in all species of Tapinochoerus, there is no clear dividing
line between the crown and the roots.
Only one other specimen of this species is in the collection (M.17116&, Brit. Mus.
Palaeont. Dept.): it is another upper third molar, very similar indeed to the first, but
slightly smaller (see PI. 18, figs. 7, 8). The length of the occlusal surface is 36 mm.,
width 16 mm., maximum length 40-5 mm. and maximum height 46 mm.
DISCUSSION OF THE GENUS TAPINOCHOERUS
The genus Tapinochoerus was formed by Van Hoepen & Van Hoepen to accom-
modate specimens which were obviously not attributable to the genus Phacochoeriis,
but were regarded as being not very far removed from that genus. Subsequently,
Shaw & Cooke recognised that the specimen which Broom had described as
Notochoeriis meadowsi was a Tapinochoerus, differing from Notochoenis in the essen-
tial characters of its third molars and, more particularly, in the absence of a well
defined line of demarcation between the crown and the strongly formed roots.
Material from Olduvai, formerly described as Notochoenis dietrichi (Hopwood, 1934;
Leakey, 1942) has now been shown to belong to Tapinochoerus, but Hopwood’s para-
type has been taken as the type of Notochoeriis hopwoodi sp. nov.
All the East African specimens of Tapinochoerus meadowsi were found in deposits
formed during a pluvial period and it would appear that the species favoured a wet
habitat, probably with abundant vegetation. This is in contrast to the specimens of
true Notochoerus, most of which, except the aberrant N otochoerus compactus, were
found in deposits attributable to rather drier periods. Tapinochoerus appears to be
very common during the Kamasian pluvial period, but less common during the
Kanjeran pluvial, although present. It is not yet recorded from the earlier deposits.
In his account of the fossil pigs from the Omo River, Arambourg (1947) described
a single incomplete lower molar, which he termed Phacochoerus africanus fossilis.
This specimen proved on examination to be a tooth of Tapinochoerus meadowsi:
it was found 10 miles south of Todenyang and did not come from the main Omo beds.
EAST AFRICAN PLEISTOCENE SUIDAE
47
The exact horizon is unknown, but it is likely to be of Middle Pleistocene rather than
Lower Pleistocene age.
Dietrich (1942) hgured part of a third molar (PI. 18, hg. 143) which appears to be
Tapinochoerns rather than a Notochoerus, more particularly in view of the absence of
any clear line of demarcation between the crown and the roots. This identihcation is
not, however, certain. He also referred to the presence of a supposed Phacochoents,
which is certainly not a specimen of that genus but is probably also a Tapinochoerus.
Some of the specimens which he attributed to Hylochoerus may also be referable to
T apinochoeriis. The material described by Dietrich was collected by Dr. Kohl-Larsen.
Some of it is known to come from the Laetolil beds, the equivalent of Bed I, Olduvai,
but other specimens came from beds whose age is still uncertain.
Genus HTLOCHOERUS Thomas
Hylochoerus ant'iquus sp. nov.
(Plate 18, fig. 9)
Diagnosis. — A Hylochoerus with larger and more robust third molars than in the
living species.
Holotype. — A fragment of mandible containing the lower third and second
molars from Kanjera (Regd. M. 17088, Brit. Mus. Palaeont. Dept.).
Horizon. — There is no clear evidence of its geological horizon. It is very heavily
mineralised and may belong to the upper part of the Kanjera deposits, in which case
it would belong to the upper half of the Middle Pleistocene.
Locality. — This specimen was collected on the surface at Kanjera.
Note. — This fragment, although found on the surface, is included because it is
the only available specimen of an extinct Hylochoerus. The living species occurs in
deposits of the Upper Pleistocene in East Africa. The specimen is of importance
because it suggests that a true Hylochoerus was already fully evolved in the Middle
Pleistocene.
Description. — The fragment consists of a piece of mandible containing Ma-a in a
reasonably good state of preservation, although the extreme tip of the talonid is
missing.
As in all true Hylochoerus, the second and third molars are composed of pairs of
pillars separated from each other by deep and wide valleys. In the median line
between the valleys are one or more small pillars. The teeth are not very hypsodont
and are strongly rooted. In certain superhcial respects they recall the teeth of
Mesochoerus, from which, however, they are quite distinct in other ways. The lateral
pillars are narrow anterio-posteriorly and wide from side to side.
One of the noticeable characters of Hylochoerus is that the wear on the median
pillars between the pairs of main pillars is greater than on the paired laterals, so that,
seen in prohle, the crowns of the teeth form a series of ridges and depressions: the
lateral pairs of pillars form the fairly well dehned transverse ridges and the depressions
are the valleys between the pairs. This type of wear is seen neither in Mesochoerus
nor in any other fossil Suidae known to me and seems to be conhned to true
Hylochoerus.
48
FOSSIL MAMMALS OF AFRICA No. 14
The length of Mg.s combined is 85 mm. The measurements of M2 are: length
29 mm. and width 15-5 mm.; and of M3: length 55-5 mm. and width 17 mm. The
enamel of the pillars is covered by a very strong layer of cement.
Hylochoerus meinertzhageni O. Thomas
Examples of this species are often found in deposits of the Gamblian pluvial period
and in cave deposits of Upper Pleistocene age in Kenya. They resemble the living
animals in all respects.
DISCUSSION OF THE GENUS HYLOCHOERUS
Although several authors have described fossil Suidae from East Africa under the
generic name of Hylochoerus, starting with Hylochoerus euilus and H. grabhami, both
of Hopwood, re-examination of available material has shown that these species belong
to other and different genera.
The only true and characteristic extinct Hylochoerus represented in the collections
under review is a specimen found on the surface at Kanjera. It seems likely that it
belongs to the closing stages of the Middle Pleistocene, indicating that this genus had
become differentiated before that time. The absence of true Hylochoerus material
in most of the fossil beds is probably due to the fact that, as a forest animal, it w^as
less likely than most of the other pigs to die under the conditions leading to the
fossilisation of its bones. Deposits of the Upper Pleistocene, such as those at Gamble’s
Cave, Elmenteita, have yielded specimens of the living species of Hylochoerus in a
sub-fossiT form. It seems probable that the genus Hylochoerus was already fully
evolved by Middle Pleistocene times and that its absence in collections may be attri-
buted to ecological causes.
Genus ORTHOSTONTX nov.
Diagnosis. — Suidae with second and third upper and lower molars having an
enamel pattern recalling that of the genera N otochoerus and Tapinochoerus. Third
molars strongly hypsodont, with no dividing line separating crown from roots and in
general recalling Tapinochoerus, but on the sides of the third molars the valleys
separating the pillars are much less strongly marked than in Tapinochoerus. Second
lower molars have three approximately equal-sized pairs of lateral pillars, strongly
rooted, but hypsodont. Viewed laterally, the valleys separating the three pairs of
pillars of the second molars only just traceable. Upper canines set in the maxilla
so that they project upwards and slightly outwards. Canine teeth contain cancellous
tissue, somewhat as in Afrochoerus, and with a similar oval cross-section. The generic
name is taken from the Greek to indicate a pig with upwardly projecting tusks.
Orthostonyx br achy ops sp. nov.
(Plates 19, 20)
Diagnosis. — A species of Orthostonyx in which the third and fourth upper pre-
molars are reduced to rudimentary proportions. This decrease in size is associated
EAST AFRICAN PLEISTOCENE SUIDAE
49
with a shortening of the face, so that the posterior rim of the alveolus of the short
upper canine tooth, which has an oval cross-section, is vertically above the front of
the first molar. The anterior end of the large maxillary foramen is vertically above
the anterior portion of the second molar, a feature also associated with the exceptional
shortening of the facial region. In the living genera, the maxillary foramen is situated
approximately over the fourth premolar. The specihc name is Greek and indicates
the peculiar shortening of the face.
Syntypes. — A. A fragment of a maxilla having part of the root socket of the
canine, as well as the third and fourth premolars and the first and second molars.
(Regd. M.17113, Brit. Mus. Palaeont. Dept.).
B. A fragment of a maxilla carrying the canine tooth and the whole of its alveolar
region. (Regd. M. 18501, Brit. Mus. Palaeont. Dept.).
C. A mandibular fragment with first, second and third molars and the socket for
the roots of the fourth premolar. (Regd. M. 18502, Brit. Mus. Palaeont. Dept.).
D. A mandibular fragment with second and third molars. (Regd. M.17110&,
Brit. Mus. Palaeont. Dept.).
Horizon. — Middle Pleistocene, Kamasian deposits.
Locality. — All four specimens are from site B.K.II, Olduvai Gorge.
First Syntype. — This maxillary fragment (PI. 19, figs. 1-3) is broken posteriorly
just behind the roots of the second molar and anteriorly through the socket for the
canine, exposing the posterior part of the canine root cavity. In the palatal region,
the specimen is fractured in the region of the palatal groove, which runs from the
palatal foramina towards the front of the maxilla in most pigs. The anterior end of
the palatal foramen is visible and is situated on a level with the talon of the second
molar. The fracture of the upper margin of the specimen passes through the maxillary
foramen, leaving the lower margin exposed and intact; this fracture shows that the
foramen was large and situated vertically above the anterior portion of the second
molar, instead of much more forward as in the living genera of pigs and in most fossil
species.
canine: This tooth is missing, but the socket is partially preserved and provides
information, which is confirmed by the evidence of the second syntype. When the
specimen is orientated so that the occlusal surface of the two molars is horizontal and
in a natural plane, the wall of the socket of the canine tooth is approximately
20 degrees off the vertical. The root of the canine must have extended almost to the
plane of the palate in the opposite direction to the roots of the premolars and molars.
When the specimen is orientated in a normal position, the posterior edge of the
alveolus is situated behind and in the same vertical plane as the anterior portion
of W.
premolars: Both and P^ are preserved and are vestigial. They have been pushed
so far backwards that the fourth premolar is almost under the crown of the hrst
molar. The maximum measurements are — Pk length 5 mm. and width 4 mm.;
P^: length ii mm. and width 7 mm.
FIRST molar: This is somewhat worn and the enamel pattern obscure. It appears
to have consisted of two pairs of lateral pillars, with a number of accessory cusps
50 FOSSIL MAMMALS OF AFRICA No. 14
in the talon area. It is strongly rooted, but there is no clear line of demarcation
between the crown and the roots. Maximum length: 24 mm.; maximum width:
17 mm.
SECOND molar: This tooth is composed of three pairs of lateral pillars and a small
talon. The anterior pair of pillars is dumb-bell shaped and recalls those seen in some
Notochoerus and Tapinochoerus species. The tooth is strongly rooted. It has a maxi-
mum length, at the occlusal surface, of 36 mm. and a maximum width of 17 mm.
The posterior portion of the tooth extends backwards in a heel, as in M^ of Tapino-
choerus, so that with advancing age the third pair of pillars and the talon would
gradually disappear. The enamel of both the molars is covered by a layer of cement,
which extends along the roots of the tooth.
If nothing but the crowns of these two molars had been available, there is little
doubt that this specimen would have been attributed to the genus Tapinochoerus.
Second Syntype. — This fragment of a maxilla is fractured anteriorly in the
region of the premaxilla-maxillary suture and this fracture extends along the upper
edge of the fragment, which is represented, in general, by the line of that suture.
Posteriorly, the specimen is fractured through the maxillary foramen, leaving the
anterior portion of the foramen intact. Interiorly, the fracture has carried away that
part of the alveolar margin which normally ^rould contain the premolars and first
molar.
This specimen clearly represents an individual larger than the first syntype, for
the distance from the uppermost posterior point of the rim of the canine to the alveolus
of the first premolars is approximately 68 mm., compared with 48 mm. in the first
syntype. This great difference in size may be a sex character, for a similar range in
size linked with sex is found in living pigs.
The canine tooth, as preserved, has a maximum length of 139 mm., measured in a
straight line from the very worn tip to the broken rim of the pulp cavity at the base
of the tooth. The degree of curvature of the tooth is only slight (PI. 19, fig. 4).
An approximate measurement along the curve is 147 mm. The canine tooth carries
internally a cancellous tissue comparable to that seen in the canines of Afrochoerus
(see below) and not otherwise recorded in any living or extinct pigs. The tip of the
canine exhibits extensive wear through use, but it is not a contact facet over the lower
canines, such as one sees in living Suidae. The canine tooth is oval in cross-section.
The alveolar rim exhibits a very marked thickening on the upper face, extending
into a keel, anteriorly, towards the contact with the premaxilla. This condition is
somewhat similar to that seen in Babyroussa babyrussa (L.) and quite unlike anything
in the living pigs of Africa.
The extraordinary shortening of the face is exemplified by the fact that the
distance from a vertical line through the posterior rim of the alveolus of the canine
to the anterior rim of the maxillary foramen is only 31 mm., whereas the corres-
ponding figures of three random samples of living African pigs are 61 mm. for
Hylochoerus, 58 mm. for Potamochoerus and 67 mm. for Phacochoerus. In the much
smaller first syntype, the corresponding figure is 29 mm.
Third Syntype. — This fragment of mandible (PI. 20, figs, i, 2) was found within
a short distance of the place where the first syntype was discovered in 1952 and
EAST AFRICAN PLEISTOCENE SUIDAE
51
may represent the same individual: the state of wear of the teeth is similar and they
are of comparable size.
The attribution of this specimen to Ortho stony x hr achy ops is based partly upon
this association and partly upon the fact that it is clearly a pig which, though similar
in its enamel pattern to Notochoerus and Tapinochoerus, is nevertheless quite distinct
and fits well with Orthostonyx.
The fragment comes from the right side of the jaw. Posteriorly, the specimen is
fractured through the talonid of M3, carrying away the hindermost part of the tooth,
as well as the surrounding bone. Anteriorly, the fracture passes just in front of the
alveolus of the P4, whereas interiorly the lower border of the mandibular body has
been completely broken away. The upper rim of the mandibular foramen, which is
preserved, is situated in a line immediately beneath the roots of P4, as in Hylochoerus
and Phacochoerus.
FOURTH premolar: Only the root sockets represent this tooth and they show clearly
that it was of small size. They are situated almost under the anterior part of Mi.
FIRST molar: This is a long, narrow tooth in an advanced state of wear. There is
a weakly defined line of demarcation between the crown and the roots, a character
absent in Mg and M3. The enamel pattern is a little confused as a result of wear, but
clearly there were two pairs of lateral pillars, separated from each other by a single
median pillar, with the enamel of each pillar in the pair contacting along the median
line. There appears also to have been a projecting talonid, but only a part of this is
preserved, as with advancing age it was worn away. There is a very marked contact
facet between the hinder part of Mi and the anterior end of Mg. As preserved, the
maximum measurements are: length 24-5 mm., posterior width ii mm.
SECOND molar: a long, narrow tooth, strongly rooted, but with no clear line of
demarcation separating the crown from the roots. It is composed of three distinct
pairs of lateral pillars, the elements of the first two pairs meeting along the median
line and separated by a single median pillar, while those of the third pair are separated
by an elongate projection of the second median pillar. There is also one small acces-
sory pillar set on the labial aspect, between the first and second lateral pillars. The
tooth projects posteriorly in a marked heel in such a way that eventually, as a result
of wear, the third pair of pillars would be eliminated. Length 33 mm. ; width 13-5 mm.
THIRD molar: This tooth has been damaged posteriorly and part of the talonid is
missing, but it is clearly composed of a series of pairs of lateral pillars separated by
median pillars. Only the front pair of pillars is in full wear; the second pair is just
beginning to be used and all parts of the tooth posterior to the second pair are still
unworn, except for very slight abrasion of the second median pillar. The projecting
heel of Mg overlaps the front portion of M3, so that the most forward projecting part
of the latter tooth is down near the alveolar margin and not at the occlusal surface.
Consequently, with advancing wear, the reduction in the length of the occlusal surface
of Mg would be compensated for by an increase in the length of the occlusal surface
of M3. Owing to damage and incomplete eruption of the tooth, it is impossible to
take accurate measurements.
This specimen, with its very long and narrow molars, gives a useful indication
of the nature of the cheek teeth of Orthostonyx brachyops.
52
FOSSIL MAMMALS OF AFRICA No. 14
Fourth Syntype. — This fragment of mandible (PI. 20, fig. 3) represents a much
larger individual than the specimen described above — in much the same way that the
second syntype represents a much bigger creature than the first. It is just possible
that it is, in fact, part of the same individual as the second syntype, but this cannot
be proved. The specimen is fractured posteriorly just behind the talonid of Mg and
anteriorly in front of Mg. On the lingual aspect, a large part of the bone was missing
when the specimen was found and the rest has been chipped in the laboratory to
expose the roots of Mg and the whole of the side of Mg.
SECOND molar: This tooth is in a fairly advanced state of wear and is strongly
rooted. It has no clear dividing line separating the crown from the roots. Anteriorly,
it is slightly damaged on the lingual aspect, while posteriorly advancing wear has
somewhat reduced the talonid. As preserved, the tooth is composed of three distinct
pairs of lateral pillars, which had obviously been separated from each other by median
pillars. With advancing wear, however, the enamel of the anterior median pillar has
become joined up with that of the lingual lateral pillar; the enamel of the second
median pillar has remained distinct, but it looks as though it would have joined up in
time with that of the second lateral pillars. The first two pairs of pillars meet each
other in the median line, but the elements of the third pair are separated from each
other by a long, irregular island of enamel. Length 38 mm.; width 19 mm.
THIRD molar: This tooth is only partially erupted and the posterior half of the tooth
was still within the body of the jaw. Only the hrst three pairs of pillars are in use:
the third pair, very slightly worn. In front of the first pair, there are three small
pillars set somewhat irregularly, while between the first and second pairs there are
two median pillars. The enamel of the second pair does not quite meet in the median
line and that of the third pair is clearly separated by a group of small piUars set
medianly. The tooth has a maximum length of 80 mm., double that of the surface
in wear, and a maximum width of 20 mm. The root area and pulp cavities of this
tooth have been badly damaged by a fracture, but the height, as preserved, is 76 mm.
at the second pair of pillars.
Additional Material. — Another fragment of mandible from Olduvai, Site
B.K.II (PI. 20, fig. 4) is also attributed to Orthostonyx hrachyops (Regd. No. M. 17110a,
Brit. Mus. Palaeont. Dept.). It has the alveoli of P^, M^ lacking the crown, and the
greater part of M^. This tooth resembles in all respects the second lower molar already
described.
DISCUSSION OF THE GENUS ORTHOSTONYX
Orthostonyx is a very strange pig with an obvious relationship, as shown by its
molar teeth, to the group that includes Tapinochoerus and Notochoerus, having a
greater resemblance to the former than to the latter. The cross-section and general
structure of the upper canine teeth, on the other hand, link it with Afrochoerus. Had
the molar teeth also been of the Afrochoerus, rather than of the Tapinochoerus-
N otochoerus type, Orthostonyx might, perhaps, have been treated as a very aberrant
Afrochoerus, but in the present state of our knowledge, it seems best to keep Ortho-
stonyx as a distinct genus.
EAST AFRICAN PLEISTOCENE SUIDAE
53
Genus AFROCHOERUS Leakey
Diagnosis. — Large Suidae with hypsodont third molars composed of closely
packed series of cusps or pillars. The enamel pattern of the lateral pillars, both
occlusal and lingual, is not subcylindrical, as in Phacochoerus, but is roughly ‘Y’
shaped, the fork of the ‘Y’ being formed by a fold in the enamel anteriorly. This
character is visible in teeth which are only just entering into wear and is not due to a
fusion of pillars. The teeth have a thin coating of cement (Leakey, 1942).
Note. — This genus was founded on worn and unworn third molar teeth from
Olduvai. Sections of unworn teeth had been cut to demonstrate the effect of wear
on the enamel pattern.
Afrochoerus nicoli Leakey
(Plates 21-29)
1942 Afrochoerus nicoli Leakey, p. 188, pi. 60, bottom; text-fig. 2.
Diagnosis. — “A species of Afrochoerus in which the third molars are composed of
two lateral rows of pillars, the enamel pattern of which is exposed on worn and unworn
teeth as an elongate “Y”, the fork of the “Y” being at the anterior end. The shape
of the enamel pattern on the median pillars in slightly worn teeth is oval. It is
characteristic of the new species that even when the teeth are worn only slightly the
enamel of adjoining pillars tends to join up, this being particularly the case with the
median pillars. As far as the lateral pillars are concerned, the process of fusion of
the enamel pattern tends to take place first at the anterior end of the tooth, but in
respect of the median pillars, the posterior ones tend to join up first” (Leakey, 1942).
To this diagnosis the following may now be added: In size, Afrochoerus
nicoli was nearly twice as big as the living species of Phacochoerus. The upper
and lower third molars develop roots with advancing age, but do not show any
clear line of demarcation between the crown and roots and thus recall those of
Phacochoerus and Tapinochoerus. The canines are very specialised. Both upper and
lower canines have an oval cross-section, are very large and have a core of cancellous
osteo-dentine in the interior of the tooth, extending almost its whole length. In old
age, the cheek teeth are reduced to the third molars only, as in Phacochoerus. In the
third molars of aged specimens, there is a complete circuit of enamel all round the
tooth and the cusp pattern in the centre is reduced to two rows of elongate islands,
wider posteriorly than anteriorly, with a few scattered irregular islands.
Holotype. — A fragment of mandible containing the lower third molar, found in
Bed II at Olduvai. (Formerly Coryndon Museum No. F.3667; now registered
M. 17095, Brit. Mus. Palaeont. Dept.).
Paratypes. — Two lower molars from Olduvai, one marked F.3030 in the collec-
tions of the Coryndon Museum, from Bed IV, and the other registered M. 17094, Brit.
Mus. Palaeont. Dept., from the junction of Beds III and IV.
A detailed illustrated description of these specimens was published in 1942, and
is not repeated here, but two of them are refigured on PI. 21, figs. 1-4.
54
FOSSIL MAMMALS OF AFRICA No. 14
Horizon. — The horizon of the holotype is the Kamasian pluvial, INIiddle Pleisto-
cene, and that of the paratypes the Kanjeran pluvial, late Middle Pleistocene.
Referred Specimens. — In addition to the type specimens there is a considerable
quantity of additional material referable to Afrochoerus nicoli. Some of it is frag-
mentary, but there are many well-preserved specimens, and in two cases, the
additional material occurred as associated groups. The specimens thus associated
will be dealt with first.
These two groups are of considerable importance in the study of Afrochoerus, since
in each case the upper canine tooth is of the same type and is associated with typical
Afrochoerus molars. The canines are of a kind which appears never to have been
recorded in association with any pig teeth, and are so extraordinary that on them
alone the separation of Afrochoerus as a new genus is fully justified. Two additional
canines of the same type were found; one in the excavations at site S.H.K.II,
Olduvai, the other on the surface of Bed II.
GROUP A. — A lower right and a lower left third molar from site B.K.II, Olduvai,
together with an upper canine found at the same time and in direct association with
these two molars (PI. 21, figs. 5-8, PI. 23, fig. 3). Regd. M. 17097a, h, c, Brit. Mus.
Palaeont. Dept.
description: The two M3 were found together, one having just been eroded from
the cliff face and the other in situ about a foot away. Close by, also in situ, was the
canine tooth. No other remains of pigs were found in the immediate vicinity, although
the site (which covers a wide area) .has yielded many different pig remains. Owing
to the direct association of the canine tooth with the molars, their common origin
can be regarded as highly probable, although not proved beyond all doubt. This is,
however, confirmed by the evidence of the other associated group — B.
The molar teeth are in an identical state of wear and the occlusal surface is, in
both cases, concave from back to front. The left molar, found on the surface, is
severely damaged anteriorly and posteriorly and still has some matrix adhering to it.
The right molar specimen, found in situ, is intact, except for slight damage in the
root area. On the left molar, there are strongly formed roots on the anterior pair of
pillars. Both teeth are in an advanced state of wear and the ‘ Y’ shaped pattern of the
lateral pillars, while still visible, is much less clear than in less worn teeth, since the
enamel is beginning to join up with the enamel of the median pillars. The teeth are
of very large size and measure — Left molar: length 95 mm., width 21 mm.; right
molar: length 95 mm. (?), width 20 mm. The arrangement of the enamel pattern
compares very closely with that seen in the holotype, but these two teeth are distinctly
larger.
The associated canine tooth has been broken at about its middle point and it is
also damaged at the tip. Both in structure and size, it is a very unusual tooth.
The cross-section is roughly oval, but there is a slight groove on the anterior face.
In spite of damage, there is evidence that there was a thin layer of enamel over the
dentine. No wear facet is visible, but towards the top of the tooth there is a marked
polishing which appears to have been caused by rubbing — possibly when the tusk was
used for uprooting vegetation. A most curious feature of the tooth is that dentine
forms only a relatively thin wall under the enamel, while the interior of the tooth is
EAST AFRICAN PLEISTOCENE SUIDAE
55
composed, for the greater part of its length, of an unusual cancellous tissue, which
does not appear to be true osteo-dentine, but which must be dentine in some form.
As preserved, the specimen is 347 mm. long (measured in a straight line), but this
represents probably less than half its original length.
GROUP B. — Two upper third molars and one lower third molar from a single individual
associated with an upper canine (PI. 22, PI. 23, fig. 4). The specimens were found at
site B.K.II, Olduvai, in 1953. Regd. M.i7096a-d, Brit. Mus. Palaeont. Dept.
The two associated upper molars, specimens M. 17096(2, h, are both in an identical
state of wear and are slightly damaged. M. 17096^1 is the more complete of the two,
while M. 170966 has the anterior end of the tooth broken away. The lower m.olar,
M. 17096c, is complete, although slightly damaged in the root area. Associated with
these three molars was the anterior end of an upper canine, M. 17096, of which the
tip is perfectly preserved, but less than a third of the tooth remains.
This second association of molar teeth of the Afrochoerus type with an upper
canine similar to that found in association with the lower two molar teeth strongly
reinforces the likelihood that this very curious type of canine tooth genuinely belongs
to the genus A frochoerus, but until one of these canine teeth is found in position in an
Afrochoerus maxilla or mandibular fragment, a slight element of doubt must remain.
The upper third molar, M. 17096(2, is the first upper molar of A frochoerus nicoli
to be described, but its direct association with a typical lower third molar leaves no
doubt that it represents this genus and species. The tooth was in full wear when
death occurred, but the posterior pillars are only slightly worn. The enamel pattern
differs somewhat from that of the lower molars of the species. As in the lower molars,
there are two rows of lateral ‘Y ’-shaped pillars, but the enamel of these pillars is less
elongated than in the lower molars of the species and also less symmetrical. Further-
more, the ‘Y’-shaped pillars do not extend the full length of the tooth and at the
posterior end they are, instead, rather oval. At the anterior end of the tooth, there
is a single row of median pillars, which are rather oval in shape, but in the talon area
the median pillars consist of two rows of small islets of enamel separating the lateral
pillars. Although damaged, it is clear that there were well developed roots on the
anterior pair of pillars and shorter and less well marked roots on the second pair.
The tooth is 62 mm. long at the occlusal surface, but has a maximum length of 65 mm.,
a maximum width of 80-5 mm. and a maximum height of 72 mm.
The other upper molar, M. 170966, which is undoubtedly from the same individual,
is essentially similar to the first, although there are some differences in the enamel
pattern (see Plate 21), particularly in the median pillars. This difference between
two teeth from the same individual emphasises that too much stress should not be
laid on variation in the enamel pattern in this genus when assessing specific characters.
The tooth is damaged anteriorly: as preserved, it is 59 mm. long and must have been
about 62 mm. before it was broken; height of the tooth, as preserved, is 55 mm.
Associated with these two upper molars was a lower molar, M. 17096c. This tooth
is in exactly the same state of wear as that of the two upper molars. It is, in every
way, characteristic of the lower dentition of Afrochoerus nicoli, although somewhat
smaller than the holotype. It has an occlusal length of 66 mm., while the maximum
56 FOSSIL MAMMALS OF AFRICA No. 14
length is 79 mm. The maximum width is 17 mm. and the maximum height, as
preserved, 68 mm.
Associated with these three molars is the broken upper canine, M.i7og6^^.
It resembles in all respects the broken upper canine described in association with
the two molar teeth forming group A. The tip is perfectly preserved and shows
traces of polishing, but has no wear facet. The dentine is not very thick and inside
there is the same cancellous tissue as described in the other canine tooth. The length
of the fragment, as preserved, is 274 mm.
C. AN ISOLATED UPPER CANINE TOOTH FROM SITE B.K.II, OLDUVAI. (Regd. No.
F.3020, Coryndon Museum.)
This tooth was found on the surface at site B.K. It consists of a broken anterior
end of a huge upper canine (PI. 23, fig. 2) of the same type as those described above,
which were found in association with the molars of Afrochoerus nicoli. It is, there-
fore, ascribed to that species.
The extreme tip has been slightly damaged and the upper end of the tooth shows
signs of polishing, but does not exhibit any wear facet, such as is commonly seen in
the canines of Suidae. In the polished area, the enamel has been removed and the
dentine rubbed to a smooth surface. When this polished area is closely examined, it is
seen to carry numerous scratches, some of them longitudinal and some transverse,
which must have been caused by contact with a very hard object. One cannot be
certain that these scratches were caused during the life of the animal because it might
be that they are the result of man 'using the tooth for some purpose such as tool-
making.
In this specimen, more of the tooth is preserved than in the two previously
described. Besides the shallow groove already mentioned on the anterior face of the
tusk, there is a smaller groove on the posterior face, which does not, however, extend
to the tip. At the point of fracture, the dentine wall is only 9 mm. thick and the
whole of the internal part of the tooth is filled, as in the other canines, by the curious
cancellous tissue. As preserved, the specimen is 432 mm. long and it must have been
nearly twice this length before it was broken. The maximum measurements, near
the point of fracture, are 68 mm. across the long axis of the oval section and 47 mm.
at right angles to the first measurement.
D. AN ISOLATED UPPER CANINE TOOTH FROM SITE S.H.K.II, OLDUVAI
When found, part of the specimen was on the surface and the posterior half in situ.
The tip of the tooth had been lost, but the specimen was originally not less than
90 mm. longer than it is today. It is the largest specimen of an upper canine tooth of
this peculiar type so far recovered and in all essential details it corresponds very
closely with the three specimens already described (PI. 23, fig. i). There is no
evidence of polishing on the specimen as preserved, for that part of the tusk which
would normally show it has been broken away. The specimen, as preserved, is
509 mm. in a straight line and 615 mm. along the curve; the maximum width near
the base is 75 mm. and the anterior-posterior measurement, at right angles to this,
is 47 mm. As in all other examples of this type of tusk, the interior of the tooth is
filled with cancellous tissue. The specimen is in the Coryndon Museum.
EAST AFRICAN PLEISTOCENE SUIDAE
57
E. FRAGMENT OF SKULL FROM SITE M.L.K.II, OLDUVAI (PL 24, figS. I, 2)
This specimen was found in the upper levels of Bed II. Associated with it were
numerous hand-axes of Chellean stage 5. The fragment consists of part of the
maxillae, together with the nasal bones and parts of the palate. The upper third
molars are both preserved. The specimen has suffered lateral compression and is
distorted.
The skull is broken oh just in front of the third molars and anterior to the large
maxillary foramina. Posteriorly, the fracture is about 90 mm. behind the third
molars. Both the upper third molars are present, that on the right is in perfect
condition, but that on the left is damaged both on its buccal side and anteriorly.
The enamel pattern is similar to that of the third upper molars described above, but
there is only one median line of pillars. This may be due to the state of wear and it
would appear likely that, before attrition had progressed thus far, there were two
rows of median pillars, at least at the posterior end of the tooth. The length of the
undamaged tooth at the occlusal surface is 69 mm. and at the alveolar margin 72 mm.
The width is 23 mm.
In its measurements, this specimen compares closely with the fragmentary skull
of Tapinochoerus described earlier, showing that Afrochoerus reached great size. The
maxillary foramina are situated above the anterior ends of the third molars and are
very large; the diameter of the best preserved foramen is 22 mm. The specimen is
the property of the Coryndon Museum.
F. UPPER THIRD MOLAR FROM SITE B.K.II, OLDUVAI (PI. 25, flgS. 3, 4). Regd.
M. 17092, Brit. Mus. Palaeont. Dept.
This is a large tooth, in which the median line of pillars has a more complex enamel
pattern than that seen in some of the other upper molars described; but the individual
variation in the enamel pattern in this genus is so great that it is not to be regarded
as significant. The tooth is slightly damaged anteriorly. The length at the occlusal
surface is 72 mm. and the maximum length must have been approximately 80 mm.
The first and second pairs of pillars had well-developed roots, which have been broken
off; the remainder has a partially closed pulp cavity with rudimentary roots. Height
81 mm.; maximum width 22-5 mm.
G. UPPER THIRD MOLAR FROM SITE B.K.II, OLDUVAI (PI. 25, figS. I, 2). Regd. M.I709I,
Brit. Mus. Palaeont. Dept.
This rather small tooth is damaged anteriorly. The length at the occlusal surface
is 58 mm. and the maximum length must have been approximately 74 mm. The
height, as preserved, is 78-5 mm. and the maximum width 19-5 mm.
H. UPPER THIRD MOLAR FROM SITE B.K.II, OLDUVAI. No. I953/446, Coryndon
Museum.
This is the damaged upper third molar which has two rows of median pillars
posteriorly, as in specimen M. 17096a described in group B. Owing to damage, it is
impossible to give accurate measurements.
58 FOSSIL MAMMALS OF AFRICA No. 14
I. UPPER THIRD MOLAR FROM OLDUVAi. No. 1953/504, Coryndon Museum.
This much worn molar came from the junction of Beds II and III. The enamel
of the lateral pillars forms a continuous line round the crown, except for the two
hindermost pillars. Within this continuous enamel line are numerous irregular
enamel pillars which no longer exhibit the characteristic ‘Y’ shape of Afrochoerits.
Nevertheless, there is very little doubt that this departure from the Afrochoerns
pattern represents a very advanced stage of wear in the upper third molars of this
species. (See below, ‘O’, page 59).
J. FRAGMENT OF MANDIBLE FROM SITE C.M.K.IV, OLDUVAI (PI. 23, flgS. 7, 8). Regd.
M. 16351, Brit. Mus. Palaeont. Dept.
This specimen is a fragment of mandible with M^. This tooth is smaller and
narrower than the other third lower molars described above, but it compares closely
with both the paratypes, which are also from the higher levels at Olduvai. It is
possible that, when more specimens have been discovered, it may become necessary
to distinguish between the Afroclioerus from Bed IV, Olduvai and from Bed II and
treat them as a distinct species. For the time being, however, it seems preferable to
retain all the specimens in the species A. nicoli, while noting that those from Bed IV
are smaller and more compact. The maximum occlusal length before it was damaged
in the anterior region was approximately 72 mm.; maximum width 14 mm. and
maximum height 64-5 mm.
K. UPPER THIRD MOLAR FROM KANjERA. Regd. M.15860, Brit. Mus. Palaeont.
Dept.
The discovery of a molar of Afrochoerus nicoli at Kanjera proves that this species
extended into the country round Lake Victoria. The specimen is damaged anteriorly
and also in the region of the roots. Its enamel pattern is typical and has no special
features. The occlusal length was probably about 70 mm. before damage, the width
is 21 mm. and the height, as preserved, is 70 mm., but was much greater before the
root area was damaged.
L. UPPER THIRD MOLAR FROM SITE C.M.K.IV, OLDUVAI (PI. 25, figS. 5, 6). Regd.
M. 17093, Brit. Mus. Palaeont. Dept.
The specimen represents the rather more compact variant of Afrochoerus nicoli
that is found in the upper beds at Olduvai. It is 58 mm. long at the occlusal surface,
with a maximum length of 59 mm. There is evidence that it carried small roots on
the first and second pairs of pillars; the pulp cavity of the rest of the tooth is open.
The maximum height is 68 mm.
M. LOWER THIRD MOLAR FROM BED IV, OLDUVAI (PI. 23, figs. 5, 6). Specimen F.3030,
Coryndon Museum.
This also represents the rather more compact form of Afrochoerus nicoli.
N. FRAGMENT OF MANDIBLE FROM BED I, OLDUVAI (PI. 26, fig. l). Regd. M.I7099,
Brit. Mus. Palaeont. Dept.
This specimen consists of the anterior part of the right side of a massive
mandible. On the left, it is fractured just beyond the symphysis, so that the sym-
EAST AFRICAN PLEISTOCENE SUIDAE
59
physial line is preserved; on the right side the fracture is through the diastema
posterior to the canine. The right canine is preserved, but the tip is broken off.
This canine tooth belongs to the type described above and provisionally ascribed
to Afrochoerus. The fracture reveals a cancellous structure inside the tusk similar
to that seen in other upper canines. There is also a trace of very thin enamel over a
small area of one face of the specimen, but, owing to its having lain on the surface
for some time, most of this enamel has scaled away. The cross-section is a flat oval,
lacking the two grooves which can be seen in upper canines. The tooth is set in the
mandible at an angle of approximately 45 degrees to the long axis of the symphysis.
From the alveolar margin, the tooth projects directly forwards. There is a marked
tuberosity on the lower face of the alveolar margin.
The anterior rim of the alveolus, between the canine and the line of the symphysis,
is damaged, but it seems that all the incisors had been shed before death. Where it is
preserved, the alveolar rim is curved so as to form an overhanging projection.
Since the symphysial line is preserved, it is possible to arrive at an approximate
estimate of the anterior width of the mandible. From the outer edge of the alveolar
rim at the canine to the symphysis is 97 mm.; by doubling this figure, a width of
194 mm. of the mandible at the canines is obtained. The corresponding figure in
Mesochoerus olduvaiensis is only 132 mm., in Notochoerus compactus 121 mm. and in
Tapinochoerus meadowsi 176 mm. The length of the symphysis of this specimen is
138 mm., which is approximately the same as in the very much smaller mandible of
Mesochoerus olduvaiensis. The thickness and general massiveness is indicated by the
following measurements: maximum thickness of the symphysial area 55 mm., com-
pared with 35 mm. in Mesochoerus olduvaiensis, 32 mm. in Notochoerus and only
21 mm. in a Recent Phacochoerus.
The nature of the small patch of enamel preserved on a part of the lower face
of this tooth throws useful light upon certain other specimens from Olduvai, which
would otherwise remain unidentified. At various sites, long and nearly straight
tusks with oval cross-sections have been recovered, but they have not been regarded
as representing Suidae because of their straightness and their unusual cross-section.
These tusks, however, exhibit patches of enamel very similar to that on the tusk
in this undoubted pig mandible, so that they may now be provisionally assigned to
Afrochoerus, especially as they also have cancellous tissue, under a thin wall of
enamel.
o. PART OF A LOWER CANINE TOOTH FROM SITE D.C., OLDUVAI, on the Surface of
Bed II (PI. 26, fig. 2). M. 17098, Brit. Mus. Palaeont. Dept.
This is the anterior end of a lower canine tooth and, as preserved, it is 200 mm.
long. It has a flat oval cross-section and, at the point where it is fractured, it measures
35 mm. X 23-5 mm. On one face there is preserved a small area of very thin enamel,
of the same type as that on the lower face of the tooth in the preceding specimen.
The greater part of the surface of the tooth is polished through use (much as in an
elephant tusk), a feature which has also been noted at the ends of the upper canine
teeth of Afrochoerus nicoli. This canine, with the others described above, is, therefore,
provisionally assigned to that species.
6o FOSSIL MAMMALS OF AFRICA No. 14
p. MANDIBLE FROM KANJERA (PL 1']). Reg. No. F.1/1955, Coryndon Museum.
During a visit to Kanjera in 1955 an almost complete mandible of a fossil pig of
giant size was recovered in situ. The two molar teeth indicate that the specimen
belongs to Afrochoerus nicoli; it is the only reasonably complete mandible of this genus
and species so far found and therefore has great importance. This mandible is some-
what distorted by pressure, but is intact except for certain small parts of the ascending
rami.
The length of the mandible, from a line perpendicular to the most backwardly
projecting part of the mandible on the condyle to the front of the symphysis, is
500 mm., compared with 488 mm. in the jaw of Tapinochoerus from Olorgesailie
(see page 42). The distance from the posterior end of the third molar to the anterior
end of the diastema is 264 mm., compared with 316-5 mm. in Tapinochoerus. This
means that in Afrochocriis the size is due to the great backward projection of the
ascending rami. The width across the front of the jaw, from the outer margin of the
alveolus of one canine to the other, is 177 mm., compared with 176 mm. in the
specimen of Tapinochoerus. The narrowest width between the canines is 121-5 mm.,
compared with 120 mm, in Tapinochoerus. The length of the symphysis is 123 mm.,
compared with 139 mm. in Tapinochoerus.
In general appearance, the body of the mandible resembles the living Hylochoenis
rather than Phacochoerus or Potamochoerus. In the region of the molars there is a
lateral thickening and flaring outwards, which can be seen to a lesser degree in
Hylochoenis , but is missing in the other two living genera. As a result of the thickening
the measurements of the jaw in the region of the mid-point of the third molar are:
width 57 mm., height 68 mm., giving a ratio of 83-9. In Hylochoenis and Phaco-
choerus, the corresponding figures are:
Hylochoenis : 35 mm. 47 mm. 74'4 (I'atio)
Phacochoerus: 33 mm. 48 mm. 68-7 ( ,, )
incisors: The alveolar region of the incisor teeth is well preserved and reveals the
root sockets of six incisors. The broken roots are present in the central and median
sockets, but not in the lateral sockets. Since the state of wear of the molars (see
below) shows that the animal was of very advanced age, this retention of the six lower
incisors is of special interest. In modern Phacochoerus jaws of a similar age, the
incisors are either entirely missing or reduced to the stumps of two central ones,
while slightly younger, though also elderly, animals are usually reduced to only four
incisors, the laterals having been shed in middle age.
canines: Neither canine is present, but their sockets are preserved. These are oval
in section and measure 57 mm. x 35 mm. The section corresponds well with the tusks
described in groups A and B above found in association with Afrochoerus molars
and differs in shape from that of any other Suidae. In this respect, therefore, the
specimen confirms the inferred evidence of the true association of Afrochoerus with
these strange tusks exhibiting an oval cross-section.
CHEEK teeth: Posterior to the sockets of the canines, no teeth remain except a
broken second molar and a third molar on the left side and a third molar on the right.
Any other cheek teeth there may have been in earlier life had been shed by the time
death took place and the long wall of the alveolus is completely fused over, so that no
EAST AFRICAN PLEISTOCENE SUIDAE 6i
traces of root sockets remain. In shedding its cheek teeth until, in old age, only
third molars remain, Afrochoerus closely resembles Phacochoerus.
The wear on the second molar on the left side is so far advanced that no enamel
is left at all and only an amorphous stump of dentine is visible. The two third molars
are well preserved, but are in an advanced stage of wear. They are of very large size,
with a maximum length in each case of 85 mm. and an occlusal length of 78 mm.
Owing to the age of the animal, the normal cusp pattern of the third molar teeth
is not present. Instead, the outer edges of the lateral cusps have fused into a single
continuous band of enamel surrounding the tooth, (cf. PI. 28.)
The inner aspects of the lateral pillars have joined up with the enamel of the
median pillars to form two rows of elongate islands of enamel down the centres of
the teeth, with a few accessory islands of enamel. In order to study the changes in the
enamel pattern of the molar teeth of Afrochoerus nicoli, a lower third molar from site
B.K.II at Olduvai was sectioned by Dr. Cohen of the Oral and Dental Hospital,
Johannesburg. The sections are illustrated on Plate 28: details are given in the
explanation.
Examination of the sections shows that, for the greater part of the height of the
tooth, the characteristic pattern of the species persists, but that in the last stages of
wear — as in the jaw from Kanjera (see above) — -the enamel of the outer wall of the
various lateral pillars joins up to form a long, continuous band of enamel all round
the tooth, while the changes in the shape of the rest of the enamel pattern and the
fusion of the inner enamel wall of the lateral pillars with that of the central pillars,
lead to a pattern in which the ‘Y’ shapes are reversed and have the open part of the
‘Y’ facing posteriorly.
In Plate 27, the jaw from Kanjera is compared with jaws of modern Hylochoerus
and Phacochoerus.
Q. ASSOCIATED UPPER AND LOWER CANINES FROM SITE S.H.K.II, OLDUVAI
During excavations at site S.H.K., two tusks of the type ascribed to Afrochoerus
nicoli were found together. This fact adds one further link to the chain of evidence
which associates these curious canine teeth with Afrochoerus. The place where the
two canines were found is only about 2 feet from the spot which yielded specimen ‘D’
above and all these teeth may belong to the same individual.
Both teeth are broken off in the root area, so that their original lengths cannot be
estimated. As preserved, the lower canine has a maximum length (in a straight line)
of 391-5 mm. and of 399 mm. along the outside curve, i.e., the curve is only slight.
At the basal end, near the point of fracture, the transverse diameter of the oval cross-
section is 54 mm. and the diameter at right angles to this is 39 mm. At the tip, the
tooth is worn to what is almost a chisel edge. The thickness of the dentine wall
surrounding the cancellous osteodentine in the centre is only 5 mm. near the point of
fracture. The upper canine found with this lower one has a maximum length in a
straight line of 339 mm., but when measured along the curve the figure is 429 mm.
This great difference between the two lengths is an indication of the greater curvature
of the upper canine compared with the lower (see above) . A very noticeable feature
of the upper canine is the reduction of the transverse diameter towards the base,
where the tusk would enter the alveolus. At the extreme base, it is 48 mm., whereas
at a point 70 mm. up from the base it is 52 mm. A similar narrowing was noticed
62
FOSSIL MAMMALS OF AFRICA No. 14
in fragments of tusk from the site B.K.IL, which were chosen for sectioning to show
the internal structure of the tusk.
This upper canine, like the lower one associated with it, has a worn tip, but neither
tooth shows any contact facet, such wear as there is being due to use and not to contact
between the upper and lower teeth. As in the case of the other upper canines already
described, the oval cross-section is interrupted by a slight groove on both the anterior
and posterior faces, but neither extends to the tip. These two associated specimens
are figured on Plate 29.
DISCUSSION OF THE GENUS AFROCHOERUS
In the original description of Ajroclioerus (Leakey, 1942), the similarities in the
enamel pattern between this genus and Van s Synaptochoerns dJ\diStylochoertis,
genera which Shaw (1939) had suggested were not really separate from Phacochoerus,
were pointed out, and, further that the peculiar shape of the enamel constituting
the lateral pillars of the third molars is not the result of wear, since even in unworn
teeth the characteristic ‘Y' shape is to be seen.
Cooke (1949) questioned the generic status of Afrochoerus and added that, if it is
really distinct from Phacochoerus, it ought to be placed in Van Hoepen’s genus
Stylochoerus , which has priority.
Study of the material now available leaves no doubt whatever that the East
African pigs for which the genus Afrochoerus was created, differ completely from
Phacochoerus in numerous characters and must be separated generically. Thus the
question arises whether it is correct to retain the generic name A frochoerus or to place
these pigs in Van Hoepen’s Stylochoerus. In view of the inadequate nature of Van
Hoepen’s material and of Shaw’s statement (1939) that in the specimens described
the ‘Y’ shape is “only present in worn teeth’’, a doubt arises whether the resemblance
between A frochoerus and Stylochoerus may not be more superhcial than real. More-
over, no record can be found of the presence of any canines of the presumed
type in South Africa, either with or without Stylochoerus. It therefore seems prefer-
able, at present, to retain the genus Afrochoerus, as distinct from Stylochoerus.
In the light of increased knowledge, based upon the material described above, it is
clear that the resemblances between Afrochoerus and Phacochoerus are conhned
mainly to the third molars and to the reduction of the cheek teeth in old age. In other
respects, such as the retention of all six incisors in old age, the flaring of the mandible
and particularly the canine teeth, the differences are strongly marked.
Genus PHACOCHOERUS Cuvier
Phacochoerus altide7is altidens Shaw & Cooke
(Plate 30, figs. 1-6)
1941 Phacochoerus altidens Shaw & Cooke, p. 296, pi. 54, figs. 3, 4.
1942 Phacochoerus complectidens Leakey, p. 194, pi. 62, left; text-fig. 16
1949a Phacochoerus complectidens Leakey : Cooke, p. 40.
Diagnosis. — A species of Phacochoerus with very high crowned, hypsodont upper
and lower third molars. In the enamel pattern of both upper and lower molars there
EAST AFRICAN PLEISTOCENE SUIDAE
63
may be as many as four, or even five, parallel rows of pillars, especially in the posterior
half of the teeth. There is a tendency for the lateral pillars, in teeth which are in an
advanced state of wear, to have a ‘Y’ shaped pattern (cf. Afrochoerus). In the upper
molars, the arrangement of the two or more median rows of pillars is usually less
symmetrical than in the lower molars. There is no dividing line between the crowns
and roots of the third molars.
Holotype. — A third molar described by Shaw & Cooke (1941) and now in the
Museum of the Archaeological Survey of South Africa, Johannesburg.
Horizon and Locality. — The holotype was found on a spoil heap and not in situ.
The authors state, however, that it is not older than the second phase of the younger
gravels of the Vaal River and possibly belongs to the third phase. The age of the
younger gravels is, broadly speaking, Middle Pleistocene. My specimen came from
Bed IV, Olduvai Gorge. The new material to be described below comes in part from
the surface of Bed II and in part from Bed IV, Olduvai. Its age is also Middle
Pleistocene.
Note. — In 1942 a species of Phacochoerus from Olduvai, Bed IV was described as
Phacochoerus complectidens Leakey, while in 1941 Shaw & Cooke had described a
lower third molar from Pniel Estate on the left bank of the Vaal River under the name
of Phacochoerus altidens. There is little doubt that the holotype of the former (PI. 30,
figs. I, 2), which was originally attributed to the lower dentition, is, in fact, part of an
upper third molar and that the two specimens represent the same species. Hence
P. complectidens Leakey is a synonym of P. altidens Shaw & Cooke.
Additional Material. — Four complete, or nearly complete, teeth undoubtedly
belong to this species.
A. AN UPPER THIRD MOLAR FROM SITE M.M.K.IV, OLDUVAI (PI. 30, figS. 3, 4). Regd.
M.17104, Brit. Mus. Palaeont. Dept.
The state of wear is not sufficiently advanced to expose the hindmost part of the
talon. Anteriorly, the enamel pattern is complex and the second pair of lateral
pillars is sufficiently worn to have coalesced with adjacent smaller median pillars, so
that a ‘Y’ shaped pillar has been formed on one side and a roughly dumb-bell shaped
pillar on the other. Behind these, there are two rows of lateral pillars, separated by
two distinct parallel rows of median pillars. Length of the occlusal surface 50 mm.;
maximum length of the tooth 63 mm.; maximum width 17 mm.; maximum height
88 mm.
B. AN UPPER MOLAR FROM SITE F.C.II, OLDUVAI (PL 30, figS. 5, 6). Regd. M.I7IO5,
Brit. Mus. Palaeont. Dept.
The anterior part of the tooth is missing. The hindmost pillars are just coming
into wear. In the anterior part, as preserved, there are 'Y’ shaped pillars caused by
the fusion of the enamel of lateral pillars with that of adjacent median pillars.
Posteriorly, there are two rows of median pillars with, at one point, three median
pillars side by side. The length of the tooth cannot be given owing to damage.
Maximum width 17-5 mm.; height, as preserved, 103 mm.
64 FOSSIL MAMMALS OF AFRICA No. 14
c. A LOWER MOLAR FROM SITE c.M.K.iv, OLDUVAi. Coryndon Museum.
The enamel pattern shows two rows of asymmetrical lateral pillars separated by
one row of median pillars, which divides into two rows in the talonid. Length of the
occlusal surface 50 mm.; maximum length 63-5 mm.; maximum width 16-5 mm.;
maximum height, as preserved, 78-5 mm.
D. A LOWER MOLAR FROM SITE C.M.K.IV, OLDUVAI. Coryndon Museum.
This tooth is in a more advanced state of wear than the three described above.
The hindmost pillars of the talon are already well worn, but the anterior part of
the tooth has broken away and is missing. The enamel pattern is somewhat different
from that seen in the other specimens, for there is a tendency for the enamel of the
median rows of pillars to join together so that two round pillars fuse into a single more
elongated one. This is because of wear. The lateral pillars show a slight ‘Y’ shaped
tendency quite unlike that seen in A frochoerus. The length of the specimen cannot be
given owing to the damage anteriorly, but the maximum width is 17 mm. and the
height, as preserved, 65 mm.
Phacochoerus altide7is robustiis sub.-sp. nov.
(Plate 30, figs. 7-1 1)
Diagnosis. — A subspecies of P. altidens having very massive, thick molars, in
which the enamel is much thicker than in P. africanus or typical P. altidens. There
are four rows of pillars in both upper and lower molars and a marked tendency for the
anterior and median pillar elements to fuse in the anterior portion of the tooth to
form a ‘Y’ shaped pattern superficially resembling that in Afyochoerus. The width
of the third molars ranges from 24 mm. to 26 mm., compared with 16 mm. to 18 mm.
in typical P altidens.
Syntypes: —
1. A fragment of lower third molar. Regd. M. 17106, Brit. Mus. Palaeont. Dept.
2. A fragment of lower third molar. Regd. M.17102, Brit. Mus. Palaeont. Dept.
3. A fragment of upper third molar. Regd. M.17103, Brit. Mus. Palaeont. Dept.
Horizon. — Middle Pleistocene, Kamasian pluvial.
Locality. — All three specimens come from Olduvai Gorge; the first from site
F.L.K., Bed II, the second from Bed I and the third from Bed II. Both the latter
were from surface collections.
Description. — first syntype (PI. 30, figs. 9, 10). This is part of the talonid
of a very large and robust M3. The preserved part is 34 mm. long. It carries 14
pillars set in four parallel rows; the enamel of each pillar is very thick and the outside
of the tooth carries a thick coat of cement. The maximum width of the fragment is
26 mm. The root area is fractured and the height, as preserved, is 70 mm, but was
probably nearly 90 mm. originally.
SECOND SYNTYPE. — (PI. 30, figs. 7, 8). This is a portion of the central region of a
very large M3, from which tooth the anterior and posterior regions are broken away.
The preserved part shows four rows of pillars, of which the laterals are rather irregu-
EAST AFRICAN PLEISTOCENE SUIDAE
65
larly shaped and the median pillars slightly smaller than the others. The enamel is
very thick and there is a coating of cement. The maximum width of the fragment at
the occlusal surface is 25 mm. The root is fractured. As preserved, the height is
71 mm.
THIRD SYNTYPE. — (PI. 30, fig. ii). A fragment of including the talon, with the
anterior portion missing. It is massive and has a very hard matrix, which covers one
side and the fracture at the anterior end. The enamel is very thick, and owing to a
more advanced state of wear than in the other two specimens, that of the lateral pillars
has, in fact, joined up with the enamel of some of the median pillars, giving a ‘Y’ shape
that simulates that seen in Afrochoerus.
Discussion. — At present, this sub-species is based upon fragmentary material,
which differs so markedly in the thickness of its enamel from the typical P. altidens
that it has been given sub-specific rank. When P. altidens is better known, it may be
possible to clarify the relationship of the more robust and the more refined forms and
it is possible that P. altidens rohustus may have to be given full specific rank.
Phacochoerus africanus Gmelin
(Plate 31)
1942 Phacochoerus cf. aethiopicus (Pallas) : Leakey, p. 193, text-fig. id.
This species of Phacochoerus occurs frequently in deposits of the Upper Pleistocene
period in East Africa and there have also been suggestions of its presence in earlier
deposits. Leakey (1942) described and figured a fragment of a tooth which he
attributed to Phacochoerus cf. aethiopicus. The specimen should more correctly be
attributed to Phacochoerus africanus. Leakey also stated that there were a number
of other specimens from Olduvai, which did not appear to differ from those of the
living species. These specimens were not found in situ and it seems likely that they
may have come from Bed V, which is of Upper Pleistocene age, and not from the main
Olduvai deposits at all. Similarly, there is a well preserved specimen from Kanjera,
which appears to be a true representative of the living species, but it also was a surface
specimen and its state of fossilisation differs markedly from that of specimens which
are undoubtedly of Middle Pleistocene age in the same area; it, too, is probably of
Upper Pleistocene age.
Among the specimens found at Olduvai, which appear to represent Phacochoerus
africanus, are the following:
1. A specimen from the surface of Bed II at site M.R.K.
2. An imperfect mandible from the surface of Bed IV at site M.G.S. (M. 17162,
Brit. Mus. Palaeont. Dept.).
3. A specimen from the surface of Bed III at site F.C. (This is stained with the
red colour of Bed III, but this could be due to its having lain upon the bed
for some length of time.)
4. A specimen from site G.T.C. found on the surface.
5. Several broken teeth from Homa Mountain (Kanjera) found on the surface.
(M. 12804 & M. 17069, Brit. Mus. Palaeont. Dept.).
66
FOSSIL MAMMALS OF AFRICA No. 14
Although no specimen of Phacochoerus africanus has been found in situ in any of
the Lower or Middle Pleistocene deposits, the possibility that it does occur cannot be
ruled out completely, since these specimens are all heavily mineralised and may well
have been derived from the deposit upon which they were lying. Two examples of
teeth that seem to represent Phacochoerus, found on the surface, are figured on PI. 31.
Various authors, including Arambourg and Dietrich, have attributed certain
specimens found in Lower and Middle Pleistocene deposits to Phacochoerus africanus,
but examination of the material and illustrations shows that these identifications are
almost certainly incorrect. Arambourg’s specimen is a Tapinochoerus, and those of
Dietrich are probably also referable to that genus and not to Phacochoerus. It is,
therefore, doubtful whether Phacochoerus africanus occurs in the Middle Pleistocene
of East Africa. The species is, however, abundant in Upper Pleistocene deposits of
the Gamblian pluvial period throughout East Africa.
DISCUSSION OF THE GENUS PHACOCHOERUS
Although pigs with certain resemblances in dentition to the genus Phacochoerus
are abundant in the Lower and Middle Pleistocene of East Africa (e.g., Notochoerus,
Tapinochoerus, Metridiochoerus, Afrochoerus and Pronotochoerus) , the genus itself is
only represented in the Lower and Middle Pleistocene by the sub-species of P. altidens.
At present it is impossible to be certain whether the modern species is a direct deriva-
tive of P. altidens or whether it may have an independent Middle Pleistocene ancestor.
Specimens previously attributed to the living species of Phacochoerus, and said to
come from Middle, or Lower, Pleistocene deposits, either belong to other genera and
species, or else are surface specimens, which cannot be proved to have come from the
deposits upon which they lay.
IV. GENERAL DISCUSSION
Erom the foregoing account certain important conclusions seem to emerge.
In the first place, it seems clear that the appearance of certain new species at
different points in the Pleistocene time scale can help to provide a useful method of
dating fossiliferous deposits in East Africa and probably also in the rest of the African
continent.
Lower Pleistocene Pigs. — The pigs so far known from the Lower Pleistocene
deposits are;
1. Nyanzachoerus kanamensis
2. Pronotochoerus jacksoni
3. Mesochoerus heseloni
4. Metridiochoerus pygmaeus
5. N otochoerus euilus
6. Mesochoerus limnetes
The first four of these have not yet been recorded in deposits later than the inter-
pluvial between the Kageran and the Kamasian, but the possibility of the persistence
of a few individuals into the Kamasian pluvial cannot be excluded, since we know that
EAST AFRICAN PLEISTOCENE SUIDAE
67
many other species of mammal that were part of the common fauna of the Lower
Pleistocene (Kageran pluvial) are represented by a few survivals in the Middle Pleisto-
cene (e.g., Dinotherium bozasi and Hippopotamus imaguncula).
Notochoerus euilus, while common in the Lower Pleistocene, also occurs among the
fossils found in the deposits at Laetolil in the Southern Serengeti (see above and
Dietrich, 1942). The Laetolil deposits have been considered by some to be older than
Bed I, Olduvai, and to belong to the Lower Pleistocene, but this is not proved and
seems unlikely. More probably the Laetolil deposits are the equivalent of Bed I,
Olduvai, but represent a wholly different ecology (cf. Hopwood, 1936a).
If the Laetolil deposits should prove to be equivalent to Bed I, Olduvai, the
presence in them of Notochoerus euilus represents a survival of a Lower Pleistocene
pig into the Middle Pleistocene. Even if this is the case, this species of Notochoerus,
together with Pronotochoerus jacksoni, Mesochoerus heseloni and Nyanzachoerus
kanamensis, may be regarded as essentially Lower Pleistocene forms. If Mesochoerus
limnetes is truly distinct from Mesochoerus heseloni, it, too, appears to be confined
to the Lower Pleistocene.
Lower Middle Pleistocene Pigs. — The following species appear, for the first
time, in the lower half of the Middle Pleistocene, so far as is known at present:
1. Notochoerus comp actus
2. Potamochoerus majus
3. Mesochoerus olduvaiensis
4. Tapinochoerus meadowsi
5. Phacochoerus altidens rohustus
6. Afrochoerus nicoli
7. Orthostonyx hr achy ops
(The exact position of Metridiochoerus andrewsi is not known; probably it also belongs
here.)
Of these pigs, five represent new genera, which are not known to occur in the
Lower Pleistocene, or Kageran pluvial. These are the genera Potamochoerus,
Tapinochoerus, Phacochoerus, Orthostonyx and Afrochoerus. The other two are new
and more evolved species of Notochoerus [N. compactus) and Mesochoerus {M.
olduvaiensis) . It would seem probable that the appearance of these seven types of
Suidae in any geological deposit can be taken to indicate that the deposits concerned
are not older than the base of the Kamasian pluvial, or the beginning of the Middle
Pleistocene.
In the interpluvial between the Kamasian and the Kageran (i.e. the transition
from the lower to the upper half of the Middle Pleistocene) Notochoerus hopwoodi
appears together with Pronotochoerus nyanzae. Probably both these species were
already present during the Kamasian pluvial, but may have favoured a habitat which
seldom resulted in their appearance in the fossiliferous lacustrine deposits.
Upper Middle Pleistocene Pigs. — In the Upper Middle Pleistocene (Kanjeran
pluvial), many of the typical pigs of the Lower Middle Pleistocene (Kamasian pluvial)
survive, among them Afrochoerus nicoli, Potamochoerus majus, Tapinochoerus
meadowsi and Metridiochoerus andrewsi. Their presence in a deposit does not, there-
fore, establish a Lower Middle Pleistocene date.
68 FOSSIL MAMMALS OF AFRICA No. 14
On the other hand, the following pigs seem to appear for the first time in the
Kanjeran pluvial:
1. Phacochoerus altidens altidens
2. Hylochoerus antiquus
3. Tapinochoertis minutus
It is also possible, but not fully established, that true Phacochoerus africaniis appears
in the upper part of the Middle Pleistocene.
Upper Pleistocene Pigs. — Although the possibility of survivals from the Middle
Pleistocene cannot be ruled out, it appears that the dry period at the close of the
Middle Pleistocene resulted in the extinction of most of them in East Africa. They
may, however, have migrated into other and less arid parts of Africa and have
survived there into the Upper Pleistocene — especially in the Congo, Angola and parts
of South Africa.
In East Africa, two of the existing species of pigs, Potamochoerus koiropotamus
and Hylochoerus meinertzhageni , seem to appear for the first time in the Upper
Pleistocene, and it is probable that the living species, Phacochoerus africanus, also
belongs here and not in the closing stages of the Middle Pleistocene.
V. REFERENCES
Arambourg, C. 1943. Observations sur les Snides fossiles du Pleistocene d’Afrique. Bull. Mus. Hist.
Nat. Paris (2) 15 : 471-476, 2 figs.
1947- Contribution a I’etude geologique et paleontologique du bassin de lac Rodolphe et de la basse
vallee de I’Omo. Deuxieme partie, Paleontologie. Mission scient. Omo, 1932-1933, i, Geol.
Anthrop. : 232-562, 40 pis. Paris.
Bouet, G. & Neuville, H. 1930. Recherches sur le genre Hylochoerus. Arch. Mus. Hist. nat. Paris
(6) 5 : 215-301, pis. 1-4.
Broom, R. 1925. The evidence of a giant pig from the late Tertiaries of South Africa. Rec. Albany Mus.,
Grahamstown, 3 : 307-308, i fig.
1928. On some new mammals from the Diamond Gravels of the Kimberley District. Ann. S. Afr.
Mus., Cape Town, 22 : 439-444, 3 figs.
1931- A new extinct giant pig from the Diamond Gravels of Windsorton, South Africa. Rec.
Albany Mus., Grahamstown, 4 : 167-168, 2 figs.
Colbert, E. H. 1935. Siwalik Mammals in the American Museum of Natural History. Trans. Amer.
Phil. Soc., Philadelphia, 26 : 1-401.
Cooke, H. B. S. 1949a. Fossil mammals of the Vaal River deposits. Mem. Geol. Surv. S. Afr., Pretoria,
35 : 117 PP-. 27 pis.
1949&. The fossil Suina of South Africa. Trans. Roy. Soc. S. Afr., Cape Town, 32 : 1-44, 19 figs.
Dale, M. M. 1948. New Fossil Suidae from the Timeworks Quarry, Makapansgat, Potgietersrust.
S. Afr. Sci., Johannesburg, 2 : 114-116, 2 figs.
Dietrich, W. O. 1937. Pleistozane Suiden-Reste aus Oldoway, Deutsch-Ostafrika. Wiss. Ergebn.
Oldoway-Exped. 1913 (N.F.) 4 : 91-104, 2 pis.
1942. Altestquartare Saugetiere aus der sudlichen Serengeti, Deutsch-Ostafrika. Palaeontographica,
Stuttgart, 94, A : 43-133, 21 pis.
EAST AFRICAN PLEISTOCENE SUIDAE 69
Dreyer, T. F. & Lyle, A. 1931. New fossil mammals and man from South Africa. 60 pp., 12 pis.
Bloemfontein.
Ennouchi, E. 1954. Omochoerus maroccanus nov. sp., nouveau Suide marocain. Bull. Soc. G^ol. Fr.,
Paris (6) 3 : 649-656, 2 figs.
Hoepen, E. C. N. van & Hoepen, H. E. van. 1932. Vrystaatse wilde Varke. Paleont. Navors. nas. Mus.,
Bloemfontein, 2 : 39-62, 77 figs.
Hopwood, A. T. 1926a. Some Mammalia from the Pliocene of Homa Mountain, Victoria Nyanza. Ann.
Mag. Nat. Hist., London (9) 18 : 266-272, 2 figs.
1926&. Fossil Mammaha. In The Geology and Palaeontology of the Kaiso Bone Beds. Occ. Papers
Geol. Surv. Uganda Protect., 2 : 13-36, 3 pis.
1927. On some mammalian remains from Lake Nyasa. Quart. J. Geol. Soc., London, 83 : 442-444.
1929a. Hylochoerus grabhami, a new species of fossil pig from the White Nile. Ann. Mag. Nat.
Hist., London (10) 4 : 289-290.
1929&. A review of the fossil mammals of Central Africa. Amer. J. Sci., New Haven (5) 17 : 101-118.
1931a. Pleistocene Mammaha from Nyasaland and Tanganyika Territory. Geol. Mag., London,
68 : 133-135-
19315. Preliminary report on the fossil Mammaha. In Le.\key, L. S. B. 1931. The stone age
cultures of Kenya Colony. (Appendix C). Cambridge.
1934- New fossil mammals from Olduvai, Tanganyika Territory. Ann. Mag. Nat. Hist., London
(10) 14 : 546-550.
1936a. New and little-known fossil mammals from the Pleistocene of Kenya Colony and Tanganyika
Territory. Ann. Mag. Nat. Hist., London (10) 17 : 636-641.
19365. Earth-movements, ice ages and faunas. Geol. Mag., London, 63 : 185-188.
1939- The mammalian fossils. In O’Brien, 1939. The Prehistory of Uganda Protectorate : 308-316.
Cambridge.
Kent, P. E. 1942. The Pleistocene beds of Kanam and Kanjera, Kavirondo, Kenya. Geol. Mag.,
London, 79 : 1 17-132.
Leakey, L. S. B. 1942. Fossil Suidae from Oldoway. J. E.Afr. Uganda Nat. Hist. Soc., Nairobi, 16 :
178-196, 3 pis.
1943- New fossil Suidae from Shungura, Omo. J. E.Afr. Uganda Nat. Hist. Soc., Nairobi, 17 :45-6i,
7 pis.
Lydekker, R. 1884. Siwalik and Narbada bunodont Suina. Palaeont. Tndica, Calcutta (10) 3 : 35-104,
pis. 6-12.
Pilgrim, G. G. 1926. The fossil Suidae of India. Palaeont. Indica, Calcutta, (n.s.) 8, 4 : 1-104, 20 pis.
Shaw, J. C. M. 1938. The teeth of the South African fossil pig {Notochoerus capensis syn. meadowsi)
and their geological significance. Trans. Roy. Soc. S. Afr., Cape Town, 26 : 25-37, 6 figs.
1939- Growth-changes and variations in wart-hog third molars and their palaeontological
importance. Trans. Roy. Soc. S. Afr., Cape Town, 27 : 51-94, 9 figs.
Shaw, J. C. M. & Cooke, H. B. S. 1941. New Fossil Pig remains from the Vaal River Gravels. Trans,
Roy. Soc. S.Afr., Cape Town, 28 : 293-299, pi. 54.
Singer, R. & Keen, E. N. 1955. Fossil Suiformes from Hopefield. Ann. S. Afr. Mus., Cape Town.
42 : 169-179, pis. 20-24.
Vaufrey, R. 1947. Olorgesaillie. Un site acheuleen d’une exceptionelle richesse. Anthropologic, Esiris,
51 : 367-
1948. Les progres de la paleontologie humaine en Afrique orientale. Nature, Paris, 76 : 144-149,
5 figs.
MADE AND PRINTED IN GREAT BRITAIN BY F. MILDNER & SONS, LONDON
Figs, i,
Fig. 3.
Fig. 4.
EXPLANATION OF PLATE i
Nyanzachoerus kanamensis sp. nov.
Mandible seen from above and from the side. Note the very large third premolar. FIolotype
(M. 15882). Kanam West, Kenya. x|.
Upper third molar. Second paratype (M. 16383). Kanam West, Kenya, xi.
Fragment of mandible with second and third molars. First paratype (Coryndon Museum).
Kanam West, Kenya, xi.
72
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa., 14
Plate i
NYANZACHOERUS
EXPLANATION OF PLATE 2
Potamochoerus majus (Hopwood)
Figs, i, 2. Part of a mandible (M.17071). Bed II, Olduvai.
Potamochoerus koiropotamus Gray
Figs. 3, 4. Mandible of modern species for comparison,
x | approx.
approx.
74
Brit. Mus. {Nat. Hist.)
Fossil Mammals of Africa.^ 1 4
Plate 2
POTAMOCHOERUS
I
Figs, i, 2.
Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.
Fig. 7.
Fig. 8.
EXPLANATION OF PLATE 3
Potamochoerus majus (Hopwood)
Associated maxillary fragments of an immature individual. (M. 17075 and M. 17076).
Olduvai. X I.
Lower third molar. (M. 17074). Bed I, Olduvai. xi.
Lower canine. (M. 17073). Bed II, Olduvai. xi.
Upper third molar. (Coryndon Museum). Bed I (surface), Olduvai. xi approx.
Lower third molar. (Coryndon Museum). Olduvai. Xi.
Part of a left mandibular ramus with P3-MJ and the alveolus for P2. Holotype (M. 14682).
Olduvai. XI.
Potamochoerus koiropotamus Gray
A fragment of mandible in which P4-M2 are well preserved, and parts of the sockets of P3
and M3. (M. 17072). Lake Eyassi Deposits. Tanganyika. Xi.
76
Brit. Mus. {Nat. Hist.)
Fossil Mammals of Africa.^ 14
Plate 3
8
POTAMOCHOERUS
Figs, i,
Figs. 3,
Fig. 5.
Fig. 6.
Fig. 7.
EXPLANATION OF PLATE 4
Mesochoerus heseloni Leakey
. Two fragments of mandible. Syntypes (M. 17118a, h). Shunguru, Omo. Xi.
.. Lower second and third molars. (Coryndon Museum). Shunguru, Omo. xi approx.
Upper third molar. (M. 17078). Shunguru, Omo. Xi.
Mesochoerus grahhami (Hopwood)
Lower third molar. Holotype (M. 13253). Kosti, White Nile, 180 m. S. of Khartoum, xi.
MesocJpenis Umnetes (Hopwood)
Upper third molar. Holotype (M. 12614). Kaiso, Albert Nyanza, Uganda, xi.
78
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa.^ 14
Plate 4
MESOCHOERUS
i
EXPLANATION OF PLATE 5
Mesochoerus olduvaiensis Leakey
Lower dentition:
Fig. I. Fragment of left side of a mandible with damaged first molar. Second and third molars intact.
Holotype (M. 17090). Bed II, Olduvai. xi approx.
Fig. 2. Broken fragment of right side of a mandible with damaged first molar and with second and
third molars intact. Paratype (M. 17059). Olduvai. xi.
Fig. 3. Fragment of mandible showing the series P4-M3. (M. 17081). Olduvai.
Fig. 4. Fragment of mandible containing M3 and M2. (M. 17080). Bed I, Olduvai. xi.
Fig. 5. Isolated lower third molar. (M. 17082). Bed III, Olduvai. xi.
Upper dentition:
Fig. 6. Fragment of maxilla with second and third molars.
XI.
Fig. 7. Fragment of maxilla with second and third molars.
XI.
(M. 17077). Bed III (surface), Olduvai.
(Coryndon Museum). Bed II, Olduvai.
Brit. Mus. (Nat. Hist.')
Fossil Mammals of Africa., 14
Plate 5
EXPLANATION OF PLATE 6
Mesochoerus olduvaiensis Leakey
Fig. I. Large part of a mandible with dentition preserved on the left side. (M. 17079). Junction of
Beds III and IV, Olduvai. X^.
Fig. 2. Details of the teeth shown in Fig. i. xi.
82
Brit. Mus. {Nat. Hist.)
Fossil Mammals of Africa., 14
Plate 6
MESOCHOERUS
EXPLANATION OF PLATE 7
Mesochoerus olduvaiensis Leakey
Fig. I. Upper canine. (Coryndon Museum). Bed II, Olduvai. x| approx.
Fig. 2. Fragment of maxilla with worn third molar, found in association with the upper canine in Fig. i.
(Coryndon Museum), xi approx.
84
A
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa^ 14
Plate 7
MESOCHOERUS
%
li
Fig. I.
Fig. 2.
Fig. 3.
Figs. 4,
Fig. 6.
EXPLANATION OF PLATE 8
M etridiochoerus andrewsi Hopwood
A third upper molar seen from the grinding surface. Holotype (M. 12805). Nr. Homa Mt.
XI.
Fragment of a maxilla. The wear of the third molar is slight and the second molar is well
preserved. The wear of the first molar is so advanced that only a small stump remains.
(M. 15880). Kagua. xi.
M etridiochoerus pygmaeus sp. nov.
An upper third molar. Holotype (M. 15932). Kanam Central, x i.
Pronotochoerus jacksoni Leakey
A lower left third molar. Holotype (M. 17083). Shunguru, Omo. xi.
A lower third molar in a broken fragment of mandible. (Coryndon Museum). Marsabit
Road site, Kenya, xi.
86
Brit. Mus. {Nat. Hist.)
Fossil Mammals of Africa^ 14
Plate 8
METRIDIOCHOERUS, PRONOTOCHOERUS
I . ^ , ! lit .11
EXPLANATION OF PLATE 9
Pronotochoerus nyanzae sp. nov.
Fig. I. The left half of a mandible containing M3, M2, a much damaged Mj and a vestigial P4. Holotype
(M.15941). Rawi, site 5, near Homa Mt., Kenya. x| approx.
Fig. 2. Mandible of Recent Phacochoerus for comparison with Fig. i. x| approx.
Fig. 3. Details of crowns shown in Fig. i. xi.
Fig. 4. Details of roots of third molar in Fig. i. xi.
88
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa., 14
Plate 9
EXPLANATION OF PLATE lo
Fig. j.
Fig. 2.
Fig. 3.
Figs. 4, 5.
Figs. 6, 7.
Notochoerus euilus (Hopwood)
Occlusal view of upper third molar and damaged second molar. (Coryndon IMuseum).
Shunguru, Omo.
Labial view of the upper third and second molars in Fig. i.
Lower third molar and damaged second molar. (Coryndon Museum). Shunguru, Omo.
Occlusal and labial views of broken third molar. (M. 151176). Laetolil, Vogel River,
Tanganyika.
Occlusal and labial views of another broken third molar. (M. 15 117a). Laetolil, Vogel River,
Tanganyika.
All natural size.
Note: The clear line of demarcation between the crown and the roots can be seen in all these specimens.
It is characteristic of Notochoerus and distinguishes it from the genus Tapinochoerus.
90
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa^ 14
Plate 10
NOTOCHOERUS
EXPLANATION OF PLATE ii
Notochoerus compactus sp. nov.
Fig. I. A well-preserved mandible with the right ascending ramus missing. Syntype (M. 17084). Bed II,
Olduvai. approx.
Fig. 2. A mandible of the modern Phacochoerus for comparison with Fig. i. approx.
Fig. 3. Details of tooth pattern of the specimen illustrated in Fig. i. xi.
92
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa^ 14
Plate i r
NOTOCHOERUS
EXPLANATION OF PLATE 12
Notochoerus compactus sp. nov.
Fig. I. Fragment of mandible. (Coryndon Museum). Bed II, Olduvai. xi approx.
Fig. 2. Fragment of mandible containing third and second molars. Syntype (M. 17085). Bed II,
Olduvai. XI.
Fig. 3. Details of roots of specimen in Fig. 2. xi.
94
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa., 14
Plate 12
NOTOCHOERUS
<
«
9
1
i
i
Fig. I.
Fig. 2.
Figs. 3,
EXPLANATION OF PLATE 13
Notochoerns hopwoodi sp. nov.
Part of a lower left mandibular ramus, side view, showing details
(M. 14685). Bed III, Olduvai. (Paratype of N. dietrichi Hopwood).
Part of the same specimen showing details of the crown pattern.
Part of an upper third molar, provisionally attributed to N. hopwoodi.
(surface), Olduvai.
All natural size.
roots. Holotype
(M.17115). Bed IV
96
Brit. Mus. {Nat. Hist.)
Fossil Mammals of Africa 14
Plate 13
NOTOCHOERUS
EXPLANATION OF PLATE 14
N otochoerus cf. hopwoodi
(with modern skulls for comparison)
Fig. I. Skull of modern Phacochoerus.
Fig. 2. Skull of modern Potaniochoerus.
Fig. 3. Skull of N otochoerus cf. hopwoodi. (M. 15940). Rawi, nr. Homa Mountain.
Fig. 4. Skull of modern Hylochocrus.
Approximately
98
Brit. Mus. (Nat. Hist.')
Fossil Mammals of Africa^ 14
Plate 14
PHACOCHOERUS, POTAMOCHOERUS, NOTOCHOERUS, HYLOCHOERUS
1'
Fig. I.
Fig. 2.
Fig. 3.
EXPLANATION OF PLATE 15
Tapinochoerus meadowsi (Broom)
An almost complete mandible with the third molars just coming into full wear.
Museum). Olorgesailie.
Jaw of modern Phacochoerus for comparison with the specimen shown in Fig. i.
The lower jaw seen in Fig. i with the associated maxilla and skull fragment
(Coryndon Museum).
Much reduced: see PI. 16.
(Coryndon
in position.
100
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa., 14
Plate 15
TAPINOCHOERUS
I • /
EXPLANATION OF PLATE i6
Tapinochoerus meadowsi (Broom)
Fig. I. Details of the crov/n pattern of the dentition shown in Plate 15, fig. i.
Fig. 2. Details of the crown pattern of the upper molars in the fragment of maxilla shown in Plate 15,
fig- 3-
Approximately natural size.
102
Brit. Mus. (Nat. Hist.')
Fossil Mammals of Africa.^ 14
Plate 16
TAPINOCHOERUS
EXPLANATION OF PLATE 17
T apinochoerus meadowsi (Broom)
Figs, i, 2.
Figs. 3, 4.
Figs. 5, 6.
Figs. 7, 8.
Upper third molar, (i) labial view and (2) occlusal view showing details of crown pattern.
(M. 17108). Bed I, Olduvai.
Upper third molar. (3) labial view and (4) occlusal view showing details of crown pattern.
(M. 14684). Olduvai. (Holotype of N. dietrichi Hopwood).
Upper third molar. (5) labial view and (6) occlusal view showing details of crown pattern.
(M.17109). Bed IV, Site CMK, Olduvai.
Upper third molar. (7) labial view and (8) occlusal view showing details of crown pattern.
(M.17107). Bed II, Site BKII, Olduvai.
All natural size.
104
Brit. Mus. (Nat. Hist.')
Fossil Mammals of Africa., 14
Plate 17
TAPINOCHOERUS
• -I
Figs, i,
Figs. 3,
Figs. 5,
Figs. 7,
Fig. 9.
EXPLANATION OF PLATE 18
T apinochoerus meadowsi (Broom)
Lower third molar, (i) labial view and (2) occlusal view showing details of crown pattern.
Coryndon Museum (F.3027). Bed I, Olduvai.
Lower third molar. (3) labial view and (4) occlusal view showing details of the crown
pattern. (M.17111). Bed II, Olduvai.
T apinochoerus minutus sp. nov.
Upper third molar. Holotype (M.i7ii6a). (5) labial view and (6) occlusal view showing
details of crown pattern. Bed IV (uppermost levels), Olduvai.
Upper third molar. (7) labial view and (8) occlusal view showing details of the crown
pattern. (M.17116&). Olduvai.
Hylochoerus antiquus sp. nov.
A fragment of mandible containing the lower third and second molars. (M. 17008). Kanjera.
AU natural size.
-r*>e
Brit. Mus. (Nat. Hist.')
Fossil Mammals of Africa., 14
Plate 18
TAPINOCHOERUS, HYLOCHOERUS
tiLi*'.;
iZ
Figs, i-
Figs. 4,
EXPLANATION OF PLATE 19
Orthostonyx hrachyops sp. nov.
Fragment of a maxilla containing part of the root socket of the canine as well as the third
and fourth premolars and the first and second molars. First Syntype (M.17113). B.K. II,
Olduvai Gorge.
Fragment of maxilla with canine tooth preserved. Second Syntype (M. 18501). Site B.K.
II, Olduvai Gorge.
All natural size.
108
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa^ 14
Plate 19
ORTHO STONYX
EXPLANATION OF PLATE 20
Orthostonyx brachyops sp. nov.
Fig. I. Fragments of mandible, with first, second and third molars and the socket for the roots of the
fourth premolar. Third Syntype (M. 18502). Site B.K.II, Olduvai.
Fig. 2. The same fragment of mandible, in occlusal view, showing details of pattern.
Fig. 3. A fragment of mandible with second and third molars showing details of pattern. Fourth
Syntype (M. 171106). B.K. II, Olduvai.
Fig. 4. Another fragment of mandible showing the remains of the first molar with the crown broken
away and the greater part of the second molar. (M. 17110a). Site B.K. II, Olduvai Gorge.
All natural size.
no
Brit. Mus. {Nat. Hist.)
Fossil Mammals of Africa 14
Plate 20
ORTHO STONYX
■*
I
I'l*
I
Fig. I
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8.
EXPLANATION OF PLATE 2i
Afrochoerus nicoli Leakey
Fragment of mandible with lower third molar, crown view. Holotype (M. 17095). Bed II,
Olduvai.
The same fragment of mandible, root view.
Lower third molar, crown view. Paratype (M. 17094). Junction of Beds III and IV, Olduvai.
The same tooth showing the pattern when sectioned halfway down.
Lower third molar showing root area. (M.ijogya). Bed II, Olduvai.
The same tooth in crown view.
Lower third molar showing root area. (M. 170976). Bed II, Olduvai.
The same tooth, showing crown pattern.
The lower third molars illustrated in Figs. 5-8 were associated
with the upper canine in PI. 23, fig. 3.
All natural size.
II2
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa., 14
Plate 2 1
AFROCHOERUS
EXPLANATION OF PLATE 22
Afrochoerus nicoli Leakey
Fig. I. Upper third molar, root view. (M. 17096c). Bed II, Olduvai.
Fig. 2. Same tooth, crown view.
Fig. 3. Upper third molar, root view. (M.17096&). Bed II, Olduvai.
Fig. 4. Same tooth, crown view.
Fig. 5. A lower third molar in root view. (M. 17096a). Bed II, Olduvai.
Fig. 6. Same tooth, crown view.
All the above were found in association with the upper canine figure in PI. 23, fig. 4,
All natural size.
1 14
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa., 14
Plate 22
AFROCHOERUS
EXPLANATION OF PLATE 23
Fig. I.
Fig. 2.
Fig. 3.
Fig. 4.
Figs. 5, 6.
Figs. 7, 8.
Afrochoerus nicoli Leakey
An isolated upper canine tooth. Coryndon Museum. Bed II, Olduvai.
A broken anterior end of an upper canine of which the extreme tip has been shghtly
damaged. Coryndon Museum (F.3020). Bed II, Olduvai.
Upper canine tooth. (M. 17097c). Bed. II, Olduvai.
Upper canine tooth. (M.i7096i). Bed II, Olduvai.
Lower third molar. (5) labial view and (6) occlusal view showing crown pattern. Cor3’ndon
Museum (F.3030). Olduvai.
Lower third molar. (7) labial view and (8) occlusal view showing crown pattern. (M.i63Si).
Bed IV (Base), Olduvai.
Figs. I, 2, 3, 4 much reduced (>5).
Figs. 5, 6, 7, 8 natural size.
I16
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa.^ 14
Plate 23
AFROCHOERUS
EXPLANATION OF PLATE 24
Afrochoerus nicoli Leakey
Fig. I. Fragment of skull. Coryndon Museum. Bed II, Olduvai. x|.
Fig. 2. Occlusal view showing the details of crown pattern of the two molars of the same specimen.
XI approx.
I18
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa., 14
Plate 24
AFROCHOERUS
Figs, i,
Figs. 3,
Figs. 5,
EXPLANATION OF PLATE 25
Afwchoerus nicoli Leakey
Upper third molar, (i) labial view. (2) occlusal view showing details of the crown formation.
(M.17091). Bed II, Olduvai.
Upper third molar. (3) labial view. (4) occlusal view showing details of crown pattern.
(M. 17092). Bed II, Olduvai.
Upper third molar. (5) labial view. (6) occlusal view showing details of crown pattern.
(M. 17093). Bed IV, Olduvai.
All natural size.
120
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa, 14
Plate 25
AFROCHOERUS
EXPLANATION OF PLATE 26
Afrochoerus nicoli Leakey
Fig. I. Fragment of mandible showing the right lower canine with the tip broken off. (M. 17099).
Surface find, Olduvai. Much reduced (59 : 100).
Fig. 2. The tip of a lower canine. (M. 17098). Bed II (Surface), Olduvai. xi.
122
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa., 14
Plate 26
AFROCHOERUS
EXPLANATION OF PLATE 27
Afrochoerus nicoli Leakey
Fig. I. An almost complete mandible compared with those of Phacochoerm africanus (right) and
Hylochoerus meinertzhageni {{qH) . Coryndon Museum (F.1/1955). Kanjera. Much reduced (<^).
Fig. 2. Crown view of the two molar teeth seen in Fig. i showing details of pattern, xi.
124
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa^ 14
Plate 27
AFROCHOERUS
EXPLANATION OF PLATE 28
Afrochoerus nicoli Leakey
(Sections through a molar tooth to show change in pattern with age.)
Fig. I. Occlusal surface of molar tooth when found.
Fig. 2. Section of the same tooth about 18 mm. further down and parallel with the occlusal surface.
Fig. 3. A similar section of the same tooth a further 25 mm. down.
Fig. 4. Another section 20 mm. further down.
All natural size.
126
Brit, Mus. {Nat. Hist.)
Fossil Mammals of Africa, 1 4
Plate 28
AFROCHOERUS
EXPLANATION OF PLATE 29
Afrochoerus nicoli Leakey
Associated upper and lower canines in lateral view showing the difference in curvature. Bed II, Olduvai.
(Coryndon Museum).
Much reduced.
128
Brit, Mus, (Nat. Hist.')
Fossil Mammals of Africa., 14
Plate 29
AFROCHOERUS
EXPLANATION OF PLATE 30
Phacochoerus altidens altidens Shaw & Cooke
Figs, i,
Figs. 3,
Figs. 5,
Figs. 7,
Figs. 9,
Fig. II.
2. Fragment of a lower third molar, labial and occlusal views. Type specimen of Phacochoerus
complectidens Leakey (1942 : 194, pi. 62, left, text-fig. xe). Coryndon Museum. Bed IV,
Olduvai.
4. Upper third molar. (3) labial view. (4) occlusal view showing crown pattern of tooth.
(M.17104). Bed IV, Olduvai.
6. An upper molar with the anterior part missing. (5) labial view. (6) occlusal view showing
crown pattern of the tooth. (M.17105). Bed II, Olduvai.
Phacocochoerus altidens robustus sub-sp. nov.
8. Part of the central region of a very large lower third molar. (7) labial view. (8) occlusal
view showing crown pattern. (M.17102). Second Syntype. Bed I, Olduvai.
10. Part of the talonid of a very large lower third molar. (9) labial view. (10) occlusal view
showing crown pattern. (M. 17106). First Syntype. Bed II (surface), Olduvai.
Fragment of a third upper molar, including the talon, with the anterior portion missing
(M.17103). Third Syntype. Bed II, Olduvai.
All natural size.
130
Brit. Mus. (Nat. Hist.)
Fossil Mammals of Africa., 14
Plate 30
PHACOCHOERUS
Figs, i, 2.
Figs. 3, 4.
EXPLANATION OF PLATE 31
Phacochoerus africanus (Gmelin)
Molar tooth, labial and occlusal views. (M,i7ioo). Bed II (surface), Olduvai.
Molar tooth, labial and occlusal views. (M.17101). Bed III (surface), Olduvai.
All natural size.
132
Plate 3 1
Brit. Mus. {Nat. Hist.)
Fossil Mammals of Africa 14
PHACOCHOERUS
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